fix(deps): update dependency graphql to v15

Author: renovate-bot

package-lock.json

@@ -31,7 +31,7 @@
   "dependencies": {
     "apollo-server-lambda": "2.25.2",
     "aws-sdk": "2.1004.0",
-    "graphql": "14.7.0",
+    "graphql": "15.6.1",
     "graphql-relay": "0.6.0"
   },
   "devDependencies": {