diff --git a/Cargo.lock b/Cargo.lock
index 21ef511..ec0c51a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,7 +2,7 @@
 # It is not intended for manual editing.
 [[package]]
 name = "KIT-ILIAS-downloader"
-version = "0.2.3"
+version = "0.2.4"
 dependencies = [
  "error-chain",
  "futures-util",
@@ -100,9 +100,9 @@ dependencies = [
 
 [[package]]
 name = "backtrace-sys"
-version = "0.1.36"
+version = "0.1.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78848718ee1255a2485d1309ad9cdecfc2e7d0362dd11c6829364c6b35ae1bc7"
+checksum = "18fbebbe1c9d1f383a9cc7e8ccdb471b91c8d024ee9c2ca5b5346121fe8b4399"
 dependencies = [
  "cc",
  "libc",
@@ -658,9 +658,9 @@ checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
 
 [[package]]
 name = "js-sys"
-version = "0.3.37"
+version = "0.3.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a27d435371a2fa5b6d2b028a74bbdb1234f308da363226a2854ca3ff8ba7055"
+checksum = "fa5a448de267e7358beaf4a5d849518fe9a0c13fce7afd44b06e68550e5562a7"
 dependencies = [
  "wasm-bindgen",
 ]
@@ -773,9 +773,9 @@ dependencies = [
 
 [[package]]
 name = "mio"
-version = "0.6.21"
+version = "0.6.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "302dec22bcf6bae6dfb69c647187f4b4d0fb6f535521f7bc022430ce8e12008f"
+checksum = "fce347092656428bc8eaf6201042cb551b8d67855af7374542a92a0fbfcac430"
 dependencies = [
  "cfg-if",
  "fuchsia-zircon",
@@ -804,9 +804,9 @@ dependencies = [
 
 [[package]]
 name = "mio-uds"
-version = "0.6.7"
+version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "966257a94e196b11bb43aca423754d87429960a768de9414f3691d6957abf125"
+checksum = "afcb699eb26d4332647cc848492bbc15eafb26f08d0304550d5aa1f612e066f0"
 dependencies = [
  "iovec",
  "libc",
@@ -837,9 +837,9 @@ dependencies = [
 
 [[package]]
 name = "net2"
-version = "0.2.33"
+version = "0.2.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42550d9fb7b6684a6d404d9fa7250c2eb2646df731d1c06afc06dcee9e1bcf88"
+checksum = "2ba7c918ac76704fb42afcbbb43891e72731f3dcca3bef2a19786297baf14af7"
 dependencies = [
  "cfg-if",
  "libc",
@@ -868,6 +868,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1c601810575c99596d4afc46f78a678c80105117c379eb3650cf99b8a21ce5b"
+
 [[package]]
 name = "openssl-probe"
 version = "0.1.2"
@@ -1026,9 +1032,9 @@ checksum = "8e946095f9d3ed29ec38de908c22f95d9ac008e424c7bcae54c75a79c527c694"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.10"
+version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df246d292ff63439fea9bc8c0a270bed0e390d5ebd4db4ba15aba81111b5abe3"
+checksum = "8872cf6f48eee44265156c111456a700ab3483686b3f96df4cf5481c89157319"
 dependencies = [
  "unicode-xid",
 ]
@@ -1054,9 +1060,9 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+checksum = "4c1f4b0efa5fc5e8ceb705136bfee52cfdb6a4e3509f770b478cd6ed434232a7"
 dependencies = [
  "proc-macro2",
 ]
@@ -1242,13 +1248,13 @@ dependencies = [
 
 [[package]]
 name = "ring"
-version = "0.16.12"
+version = "0.16.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ba5a8ec64ee89a76c98c549af81ff14813df09c3e6dc4766c3856da48597a0c"
+checksum = "703516ae74571f24b465b4a1431e81e2ad51336cb0ded733a55a1aa3eccac196"
 dependencies = [
  "cc",
- "lazy_static",
  "libc",
+ "once_cell",
  "spin",
  "untrusted",
  "web-sys",
@@ -1423,9 +1429,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.51"
+version = "1.0.52"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da07b57ee2623368351e9a0488bb0b261322a15a6e0ae53e243cbdc0f4208da9"
+checksum = "a7894c8ed05b7a3a279aeb79025fdec1d3158080b75b98a08faf2806bb799edd"
 dependencies = [
  "itoa",
  "ryu",
@@ -1648,9 +1654,9 @@ dependencies = [
 
 [[package]]
 name = "tokio"
-version = "0.2.19"
+version = "0.2.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d9c43f1bb96970e153bcbae39a65e249ccb942bd9d36dbdf086024920417c9c"
+checksum = "05c1d570eb1a36f0345a5ce9c6c6e665b70b73d11236912c0b477616aeec47b1"
 dependencies = [
  "bytes",
  "fnv",
@@ -1766,9 +1772,9 @@ checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 
 [[package]]
 name = "untrusted"
-version = "0.7.0"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60369ef7a31de49bcb3f6ca728d4ba7300d9a1658f94c727d4cab8c8d9f4aece"
+checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
 
 [[package]]
 name = "url"
@@ -1833,9 +1839,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2cc57ce05287f8376e998cbddfb4c8cb43b84a7ec55cf4551d7c00eef317a47f"
+checksum = "e3c7d40d09cdbf0f4895ae58cf57d92e1e57a9dd8ed2e8390514b54a47cc5551"
 dependencies = [
  "cfg-if",
  "serde",
@@ -1845,9 +1851,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-backend"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d967d37bf6c16cca2973ca3af071d0a2523392e4a594548155d89a678f4237cd"
+checksum = "c3972e137ebf830900db522d6c8fd74d1900dcfc733462e9a12e942b00b4ac94"
 dependencies = [
  "bumpalo",
  "lazy_static",
@@ -1860,9 +1866,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-futures"
-version = "0.4.10"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7add542ea1ac7fdaa9dc25e031a6af33b7d63376292bd24140c637d00d1c312a"
+checksum = "8a369c5e1dfb7569e14d62af4da642a3cbc2f9a3652fe586e26ac22222aa4b04"
 dependencies = [
  "cfg-if",
  "js-sys",
@@ -1872,9 +1878,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8bd151b63e1ea881bb742cd20e1d6127cef28399558f3b5d415289bc41eee3a4"
+checksum = "2cd85aa2c579e8892442954685f0d801f9129de24fa2136b2c6a539c76b65776"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -1882,9 +1888,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d68a5b36eef1be7868f668632863292e37739656a80fc4b9acec7b0bd35a4931"
+checksum = "8eb197bd3a47553334907ffd2f16507b4f4f01bbec3ac921a7719e0decdfe72a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1895,15 +1901,15 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.60"
+version = "0.2.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "daf76fe7d25ac79748a37538b7daeed1c7a6867c92d3245c12c6222e4a20d639"
+checksum = "a91c2916119c17a8e316507afaaa2dd94b47646048014bbdf6bef098c1bb58ad"
 
 [[package]]
 name = "web-sys"
-version = "0.3.37"
+version = "0.3.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2d6f51648d8c56c366144378a33290049eafdd784071077f6fe37dae64c1c4cb"
+checksum = "8bc359e5dd3b46cb9687a051d50a2fdd228e4ba7cf6fcf861a5365c3d671a642"
 dependencies = [
  "js-sys",
  "wasm-bindgen",