chore(deps): update dependency @types/koa to v2.0.43

Author: renovate-bot

packages/apollo-server-koa/package.json

@@ -30,7 +30,7 @@
   },
   "devDependencies": {
     "@types/graphql": "0.11.7",
-    "@types/koa": "2.0.42",
+    "@types/koa": "2.0.43",
     "@types/koa-bodyparser": "3.0.26",
     "@types/koa-router": "7.0.27",
     "apollo-server-integration-testsuite": "^1.3.0",