fix: upgrade @apollo/client from 3.0.2 to 3.6.8

Snyk has created this PR to upgrade @apollo/client from 3.0.2 to 3.6.8.

See this package in npm:
https://www.npmjs.com/package/@apollo/client

See this project in Snyk:
https://app.snyk.io/org/contentstack-ecosystem/project/bb48899f-43b7-42e5-bb5a-5324b1f36a23?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

package-lock.json

@@ -10,7 +10,7 @@
     "lint": "eslint ."
   },
   "dependencies": {
-    "@apollo/client": "^3.0.2",
+    "@apollo/client": "^3.6.8",
     "apollo-client": "^2.6.10",
     "graphql": "^15.3.0",
     "react": "16.13.1",