Update dependency koa to v2.13.0

Author: renovate-bot

package-lock.json

@@ -33,7 +33,7 @@
     "config": "3.2.4",
     "dotenv-safe": "8.2.0",
     "ethers": "4.0.47",
-    "koa": "2.11.0",
+    "koa": "2.13.0",
     "koa-body": "4.1.1",
     "koa-combine-routers": "4.0.2",
     "koa-compress": "3.0.0",