chore(deps): bump koa from 2.12.1 to 2.13.0

Bumps [koa](https://github.com/koajs/koa) from 2.12.1 to 2.13.0.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/master/History.md)
- [Commits](https://github.com/koajs/koa/compare/2.12.1...2.13.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -91,7 +91,7 @@
     "jsdom": "16.2.2",
     "json-bigint": "0.3.1",
     "json5": "2.1.3",
-    "koa": "2.12.1",
+    "koa": "2.13.0",
     "koa-basic-auth": "4.0.0",
     "koa-favicon": "2.1.0",
     "koa-mount": "4.0.0",

yarn.lock

@@ -7571,10 +7571,10 @@ koa-mount@4.0.0:
     debug "^4.0.1"
     koa-compose "^4.1.0"
 
-koa@2.12.1:
-  version "2.12.1"
-  resolved "https://registry.yarnpkg.com/koa/-/koa-2.12.1.tgz#a0ab4dcfebe3cc1b6f0875cbfd686edd7e926643"
-  integrity sha512-NuYVKjnBxeEe19VljPO9yNcaKKVrMagcax3jjzZtOlxRY2nThWKQqgnI3Pr1OG7mFtvySoDRixoUWZIt6R9C3A==
+koa@2.13.0:
+  version "2.13.0"
+  resolved "https://registry.yarnpkg.com/koa/-/koa-2.13.0.tgz#25217e05efd3358a7e5ddec00f0a380c9b71b501"
+  integrity sha512-i/XJVOfPw7npbMv67+bOeXr3gPqOAw6uh5wFyNs3QvJ47tUx3M3V9rIE0//WytY42MKz4l/MXKyGkQ2LQTfLUQ==
   dependencies:
     accepts "^1.3.5"
     cache-content-type "^1.0.0"