Add support for bigint
### Issue Description

If the response contains `bigint` values, the following error occurs:
```json
{
    "errors": [
        {
            "message": "Do not know how to serialize a BigInt",
            "extensions": {
                "code": "INTERNAL_SERVER_ERROR",
                "exception": {
                    "stacktrace": [
                        "TypeError: Do not know how to serialize a BigInt",
                        "    at JSON.stringify (<anonymous>)",
                        "    at prettyJSONStringify (/Users/oxilor/Projects/personal/apollo-server-bigint-issue/node_modules/apollo-server-core/src/runHttpQuery.ts:576:15)",
                        "    at processHTTPRequest (/Users/oxilor/Projects/personal/apollo-server-bigint-issue/node_modules/apollo-server-core/src/runHttpQuery.ts:461:14)",
                        "    at processTicksAndRejections (node:internal/process/task_queues:95:5)"
                    ]
                }
            }
        }
    ]
}
```

### Link to Reproduction

https://github.com/oxilor/apollo-server-bigint-issue

### Reproduction Steps

1. Run `yarn start`.
2. Make a request to `http://localhost:4000/graphql` with the the following query (e.g. using Postman):

```graphql
query Query {
  region {
    id
    population
  }
}
```