Hey!

I'm generating the introspection types in a directory that is git-ignored, and graphqlsp does not create this directory automatically if not found

What do you think about adding something roughly like this?

if (output.endsWith('.ts')) {
  await mkdir(path.dirname(output), { recursive: true });
}

(with proper error handling of course)

Ref:

I'd be happy to contribute a pull request if this change is accepted