feat(gatsby-source-medium): define types explicitly via createSchemaCustomization (#20069)

[Powell-v2]

Description

Use createSchemaCustomization for explicit type declarations in gatsby-source-medium plugin.

Related Issues

Umbrella issue => #20069

[vladar]

Great job! 🎉

One problem is that Medium seems to have several fields that are available conditionally. I took official gatsby medium example and compared schema produced for it against the schema from this PR - and there are some differences. See the diff.

So I suggest the following changes:

1. Remove @dontInfer directive for now because it may lead to breaking changes. We will probably add it to the next major version of this plugin.
2. Remove @derivedTypes directive - as it is unnecessary.
3. Add fields from the diff above to this PR (that gist contains both schema files if you need to make diffs locally).
4. Make all types uppercase (not sure why some of them are lowercased)?

Please let me know what you think and thanks a lot for the PR! It helps our schema customization initiative a lot!

[vladar]

Awesome, thanks for update! I will try it locally (hopefully tomorrow) and merge.

[vladar]

Looks good to me. Let's ship it 🚢

And thank you for your interest in helping us with schema customization!

[gatsbot]

Holy buckets, @Powell-v2 — we just merged your PR to Gatsby! 💪💜

Gatsby is built by awesome people like you. Let us say “thanks” in two ways:

1. We’d like to send you some Gatsby swag. As a token of our appreciation, you can go to the Gatsby Swag Store and log in with your GitHub account to get a coupon code good for one free piece of swag. We’ve got Gatsby t-shirts, stickers, hats, scrunchies, and much more. (You can also unlock even more free swag with 5 contributions — wink wink nudge nudge.) See gatsby.dev/swag for details.
2. We just invited you to join the Gatsby organization on GitHub. This will add you to our team of maintainers. Accept the invite by visiting https://github.com/orgs/gatsbyjs/invitation. By joining the team, you’ll be able to label issues, review pull requests, and merge approved pull requests.

If there’s anything we can do to help, please don’t hesitate to reach out to us: tweet at @gatsbyjs and we’ll come a-runnin’.

Thanks again!