feat: upgrade graphql from 15.0.0 to 16.12.0

Snyk has created this PR to upgrade graphql from 15.0.0 to 16.12.0.

See this package in npm:
graphql

See this project in Snyk:
https://app.snyk.io/org/gregbrimble/project/d78861a6-63c6-4c43-a55b-cd5a9cc8a515?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

packages/server/package.json

@@ -18,7 +18,7 @@
   "dependencies": {
     "@kv-orm/cf-workers": "2.0.1",
     "@kv-orm/core": "0.1.1",
-    "graphql": "15.0.0",
+    "graphql": "16.12.0",
     "graphql-iso-date": "3.6.1",
     "graphql-scalars": "1.1.2",
     "graphql-tag": "2.10.3",