fix(gatsby-transformer-sharp): define required image fields as non-null in schema

[daugsbi]

Description

The generated graphql schema have a lot of nullable fields which are required for images (i.e. the src of an image). This makes it incompatible to use it with type generators and TypeScript.

This PR changes the gatsby-source-contentful and the gatsby-transformer-sharp to be at least compatible with the gatsby-image type definitions.

Documentation

Docs should exist already. I don't expect that they include such details.

Related Issues

This PR should close #17003.

[Kerumen]

Thanks!

[vladar]

Good suggestion! It makes perfect sense. Left one request for a change (minor change for consistency). Then we are good to go!

[vladar]

Looking good to me, thanks for the PR!

[gatsbot]

Holy buckets, @daugsbi — 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!