feat: show @oneOf in introspection query

[erikwrede]

This PR ports graphql/graphql-js#4078 to python to ease the adoption of the new oneOf directive freshly contained in the new spec release. As requested by strawberry issue strawberry-graphql/strawberry#3975

I left out the tests to src/utilities/__tests__/buildClientSchema-test.ts, as I couldn't find a matching file containing all relevant tests. Feel free to let me know if you desire any changes 😊

[codspeed-hq]

CodSpeed Performance Report

Merging #241 will not alter performance

_{Comparing erikwrede:feat/one-of-introspection (12abac7) with main (fa8f9b5)}

Summary

✅ 14 untouched

[leszekhanusz]

In graphql-python/gql#569, I added the same functionality to request isOneOf in the introspection query.

Downloading a schema with it from the console should be possible with gql-cli https://SERVER_URL/graphql --print-schema --schema-download input_object_one_of:true > schema.graphql

Now, does anyone knows any public backend which allows introspection and has isOneOf in its schema to test this?

[Cito]

Thank you @erikwrede. Will merge next week, fix linting and add the missing tests, you don't need to bother.

Sorry for lagging behind.