Use latest version of graphql

[CharlieGreenman]

This repo is on 15 and latest is 16. Causing multiple issues when trying to use latest packages and npm

[julianpung]

And even graphql 15 is not supported in the subpackages, which results in conflicting peer dependencies, creating a npm warning when installing dependencies.

From package-lock.json:

"node_modules/aws-appsync-auth-link/node_modules/apollo-link": {
  "version": "1.2.5",
  "resolved": "https://registry.npmjs.org/apollo-link/-/apollo-link-1.2.5.tgz",
  "integrity": "sha512-GJHEE4B06oEB58mpRRwW6ISyvgX2aCqCLjpcE3M/6/4e+ZVeX7fRGpMJJDq2zZ8n7qWdrEuY315JfxzpsJmUhA==",
  "license": "MIT",
  "dependencies": {
    "apollo-utilities": "^1.0.0",
    "zen-observable-ts": "^0.8.12"
  },
  "peerDependencies": {
    "graphql": "^0.11.3 || ^0.12.3 || ^0.13.0 || ^14.0.0"
  }
},