chore(deps): update dependency apollo-server to v2.9.15

Author: renovate-bot

examples/hooks/server/package.json

@@ -2,7 +2,7 @@
   "name": "hooks-demo-server",
   "description": "",
   "dependencies": {
-    "apollo-server": "2.9.14",
+    "apollo-server": "2.9.15",
     "apollo-server-express": "2.9.14",
     "express": "4.17.1",
     "graphql": "14.5.8",