diff --git a/yarn.lock b/yarn.lock
index 868f95d..d0773f1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -714,12 +714,12 @@ convert-source-map@^1.4.0, convert-source-map@^1.5.1:
   dependencies:
     safe-buffer "~5.1.1"
 
-cookies@~0.7.1:
-  version "0.7.2"
-  resolved "https://registry.yarnpkg.com/cookies/-/cookies-0.7.2.tgz#52736976126658af7713d7f858f7d21f99dab486"
+cookies@~0.8.0:
+  version "0.8.0"
+  resolved "https://registry.yarnpkg.com/cookies/-/cookies-0.8.0.tgz#1293ce4b391740a8406e3c9870e828c4b54f3f90"
   dependencies:
-    depd "~1.1.2"
-    keygrip "~1.0.2"
+    depd "~2.0.0"
+    keygrip "~1.1.0"
 
 copy-descriptor@^0.1.0:
   version "0.1.1"
@@ -846,7 +846,11 @@ delegates@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/delegates/-/delegates-1.0.0.tgz#84c6e159b81904fdca59a0ef44cd870d31250f9a"
 
-depd@^1.1.2, depd@~1.1.2:
+depd@^2.0.0, depd@~2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/depd/-/depd-2.0.0.tgz#b696163cc757560d09cf22cc8fad1571b79e76df"
+
+depd@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/depd/-/depd-1.1.2.tgz#9bcd52e14c097763e749b274c4346ed2e560b5a9"
 
@@ -893,16 +897,16 @@ ee-first@1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/ee-first/-/ee-first-1.1.1.tgz#590c61156b0ae2f4f0255732a158b266bc56b21d"
 
+encodeurl@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/encodeurl/-/encodeurl-1.0.2.tgz#ad3ff4c86ec2d029322f5a02c3a9a606c95b3f59"
+
 error-ex@^1.2.0:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/error-ex/-/error-ex-1.3.2.tgz#b4ac40648107fdcdcfae242f428bea8a14d4f1bf"
   dependencies:
     is-arrayish "^0.2.1"
 
-error-inject@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/error-inject/-/error-inject-1.0.0.tgz#e2b3d91b54aed672f309d950d154850fa11d4f37"
-
 es-abstract@^1.5.1:
   version "1.12.0"
   resolved "https://registry.yarnpkg.com/es-abstract/-/es-abstract-1.12.0.tgz#9dbbdd27c6856f0001421ca18782d786bf8a6165"
@@ -2075,9 +2079,11 @@ jsprim@^1.2.2:
     json-schema "0.2.3"
     verror "1.10.0"
 
-keygrip@~1.0.2:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/keygrip/-/keygrip-1.0.3.tgz#399d709f0aed2bab0a059e0cdd3a5023a053e1dc"
+keygrip@~1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/keygrip/-/keygrip-1.1.0.tgz#871b1681d5e159c62a445b0c74b615e0917e7226"
+  dependencies:
+    tsscmp "1.0.6"
 
 kind-of@^3.0.2, kind-of@^3.0.3, kind-of@^3.2.0:
   version "3.2.2"
@@ -2127,24 +2133,20 @@ koa-convert@^1.2.0:
     co "^4.6.0"
     koa-compose "^3.0.0"
 
-koa-is-json@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/koa-is-json/-/koa-is-json-1.0.0.tgz#273c07edcdcb8df6a2c1ab7d59ee76491451ec14"
-
 koa@^2.5.3:
-  version "2.5.3"
-  resolved "https://registry.yarnpkg.com/koa/-/koa-2.5.3.tgz#0b0c37eee3aac807a0a6ad36bc0b8660f12d83f1"
+  version "2.13.1"
+  resolved "https://registry.yarnpkg.com/koa/-/koa-2.13.1.tgz#6275172875b27bcfe1d454356a5b6b9f5a9b1051"
   dependencies:
     accepts "^1.3.5"
     cache-content-type "^1.0.0"
     content-disposition "~0.5.2"
     content-type "^1.0.4"
-    cookies "~0.7.1"
+    cookies "~0.8.0"
     debug "~3.1.0"
     delegates "^1.0.0"
-    depd "^1.1.2"
+    depd "^2.0.0"
     destroy "^1.0.4"
-    error-inject "^1.0.0"
+    encodeurl "^1.0.2"
     escape-html "^1.0.3"
     fresh "~0.5.2"
     http-assert "^1.3.0"
@@ -2152,7 +2154,6 @@ koa@^2.5.3:
     is-generator-function "^1.0.7"
     koa-compose "^4.1.0"
     koa-convert "^1.2.0"
-    koa-is-json "^1.0.0"
     on-finished "^2.3.0"
     only "~0.0.2"
     parseurl "^1.3.2"
@@ -3355,6 +3356,10 @@ ts-jest@^23.10.3:
     semver "^5.5"
     yargs-parser "10.x"
 
+tsscmp@1.0.6:
+  version "1.0.6"
+  resolved "https://registry.yarnpkg.com/tsscmp/-/tsscmp-1.0.6.tgz#85b99583ac3589ec4bfef825b5000aa911d605eb"
+
 tunnel-agent@^0.6.0:
   version "0.6.0"
   resolved "https://registry.yarnpkg.com/tunnel-agent/-/tunnel-agent-0.6.0.tgz#27a5dea06b36b04a0a9966774b290868f0fc40fd"