fix(deps): update dependency koa to v2.5.3 (#423)

Author: renovate[bot]

package-lock.json

@@ -45,7 +45,7 @@
     "form-data": "2.3.2",
     "inversify": "4.13.0",
     "joi": "13.6.0",
-    "koa": "2.5.2",
+    "koa": "2.5.3",
     "koa-body": "4.0.4",
     "koa-cors": "0.0.16",
     "koa-helmet": "4.0.0",