ENOENT: no such file or directory, open './schema.graphql'

### Issue Description

Going over docs I stuck on https://www.apollographql.com/docs/apollo-server/workflow/generate-types
The documentation says:
"move your server's schema into a .graphql file" and then use it like so:

```
// ...other imports
import { readFileSync } from 'fs';

// Note: this uses a path relative to the project's
// root directory, which is the current working directory
// if the server is executed using `npm run`.
const typeDefs = readFileSync('./schema.graphql', { encoding: 'utf-8' });
```

Error:
```
node:fs:592
handleErrorFromBinding(ctx);
^

Error: ENOENT: no such file or directory, open './schema.graphql'
at Object.openSync (node:fs:592:3)
at readFileSync (node:fs:460:35)
at file:///Users//index.js:6:18
at ModuleJob.run (node:internal/modules/esm/module_job:192:25) {
errno: -2,
syscall: 'open',
code: 'ENOENT',
path: './schema.graphql'
}

```

### Link to Reproduction

https://github.com/egor-sorokin/graphql-try

### Reproduction Steps

- install dependecies
- run `npm run start`

Start with the generate-types documentation linked in the issue and reproduce the failure using the linked graphql-try project and `npm run start`. Check how the example resolves `schema.graphql` relative to the working directory; done means the documented setup no longer produces ENOENT or clearly explains the required file location.

Written by the indexing model from the issue text.