Bump koa from 2.15.4 to 2.16.1 (#32)

Bumps [koa](https://github.com/koajs/koa) from 2.15.4 to 2.16.1.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/master/History.md)
- [Commits](koajs/koa@2.15.4...v2.16.1)

---
updated-dependencies:
- dependency-name: koa
  dependency-version: 2.16.1
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package.json

@@ -14,7 +14,7 @@
   "dependencies": {
     "@koa/cors": "^5.0.0",
     "@teamwork/websocket-json-stream": "^2.0.0",
-    "koa": "^2.15.4",
+    "koa": "^2.16.1",
     "koa-bodyparser": "^4.4.1",
     "koa-easy-ws": "^2.1.0",
     "sharedb": "^5.1.1",

yarn.lock

@@ -758,10 +758,10 @@ koa-easy-ws@^2.1.0:
   dependencies:
     debug "^4.1.1"
 
-koa@^2.15.4:
-  version "2.15.4"
-  resolved "https://registry.yarnpkg.com/koa/-/koa-2.15.4.tgz#7000b3d8354558671adb1ba1b1c09bedb5f8da75"
-  integrity sha512-7fNBIdrU2PEgLljXoPWoyY4r1e+ToWCmzS/wwMPbUNs7X+5MMET1ObhJBlUkF5uZG9B6QhM2zS1TsH6adegkiQ==
+koa@^2.16.1:
+  version "2.16.1"
+  resolved "https://registry.yarnpkg.com/koa/-/koa-2.16.1.tgz#ba1aae04d8319d7dac4a17a0d289d7482501e194"
+  integrity sha512-umfX9d3iuSxTQP4pnzLOz0HKnPg0FaUUIKcye2lOiz3KPu1Y3M3xlz76dISdFPQs37P9eJz1wUpcTS6KDPn9fA==
   dependencies:
     accepts "^1.3.5"
     cache-content-type "^1.0.0"