feat(theme): update gatsby to v3

[joshblack]

Migration guide

Checklist

• @primer/gatsby-theme-doctocat
  • Update Gatsby to 3.x
  • Update peerDependency to 3.x
  • Update Gatsby related packages (Reference)
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.4.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.0".
    • [email protected]" has unmet peer dependency "babel-plugin-styled-components@>1.5.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.32".
    • [email protected]" has incorrect peer dependency "gatsby@^2.2.0".
    • [email protected]" has incorrect peer dependency "gatsby@^2.0.15".
  • Add peer dependencies for gatsby-plugin-styled-components (babel-plugin-styled-components and styled-components)
• docs
  • Update Gatsby to 3.x
  • Change __experimentalThemes to plugins in docs (Reference)

Sites

• feat: update gatsby to v3 and doctocat primer.style#330
• chore(docs): update doctocat theme react#2341

[changeset-bot]

🦋 Changeset detected

Latest commit: 770acce

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/gatsby-theme-doctocat	Major

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Click here if you're a maintainer who wants to add another changeset to this PR

[joshblack]

@colebemis ended up moving #466 over into this PR and linked some of the sites that I've done PRs for with the prerelease package.

Would you recommend other sites that use the gatsby theme that I should include? 👀

[github-actions]

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[mperrotti]

@josepmartins and I branched off of this and tried (and failed) to upgrade React and PRC.

We're running into this issue: gatsbyjs/gatsby#26785

Here's how we tried to get around it:

• The webpack build hack in this comment
• Using npm instead of yarn
• Skipping v3 and going straight to v4

[radglob]

Adding yarn resolutions for graphql and graphql-compose seems to make this work.

After adding that and linking a local copy of the repo to docs/package.json in my local copy of @primer/react

{
  "dependencies": {
    "@primer/gatsby-theme-doctocat": "../../doctocat/theme",
    ...
  }
  ...
}

Everything builds fine. No graphql issues, whole thing renders correctly.

The migration docs mention it here.

[lesliecdubs]

Bumping for review. @langermank it looks like you were auto-assigned a while back, do you have bandwidth to take a look?

[mperrotti]

Looks great. Thanks for finally getting this working @radglob !