Update dependency @koa/router to v13

Author: renovate[bot]

package.json

@@ -8,7 +8,7 @@
   "dependencies": {
     "@cloudnative/health": "^2.1.2",
     "@graphql-tools/schema": "^8.3.3",
-    "@koa/router": "^10.1.1",
+    "@koa/router": "^13.0.0",
     "apollo-server-core": "^3.6.4",
     "apollo-server-koa": "^3.6.4",
     "bluebird": "^3.7.2",