feat: generate types from schema

[G-Rath]

This is branched off #252 to avoid me having to do an ugly rebase - ideally that should be merged first to make this review-able

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Look, it's type generation!

Also ported over the code to generate the EventPayloadMap interface that can be used to do dynamic mapping.

I've made this a draft for now as while I think it's ready for review, it requires #252 and I think we should discuss how we're handling the build flow - I think it could benefit from a bit of a revision now that we've got a bit of a chain going.

In particular, do we want to check-in the schema.d.ts? Personally I think it would make reviewing easier, but we currently don't check-in the schema.json which is required by this script.

(this is currently written in TS, but can convert to JS easily if it looks like #254 isn't going to be merged for a bit)

[G-Rath]

This is needed as a fix until bcherny/json-schema-to-typescript#362 is landed.

[G-Rath]

can't statically import a file that's generated by a build command 🤦

[gr2m]

I think eventually I'd move the event types into a different repository, because they are only relevant to the JavaScript Octokit projects, but for now we can add it here.

[gr2m]

Could you add a section to the README on how to import the types? It would be good to show how to import the type for a specific event payload. That would answer @AlCalzone's question at probot/probot#1456

[G-Rath]

@gr2m done - I'll merge this shortly, and start on my refactor of webhooks.js & co 🎉

[octokitbot]

🎉 This PR is included in version 3.35.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[gr2m]

Great work everyone