feat: update github accept files to handle scaffolder

[aszarama]

Jira ticket: https://cortex1.atlassian.net/browse/CET-20674

The background is that we want to add support for scaffolder, which needs access to github (not api/graphql).

This PR just adds a validation for accept header, there's more headers than we need, but just in case something changes in the future.

This PR is breaking the contract, because it needs one additional variable "GITHUB", which is just a plain link to the github, for example "https://github.com".

[aszarama]

Currently it will fail some tests. I'm not sure how we want to deal with these changes for scaffolder, is it gonna be mentioned only in the docs, or we want to make a change for all customers, but require them to add new variable.

[aszarama]

Hey @shawnburke, figured out how to deal with scaffolder. Turns out we just have to handle two requests to the github.

I was able to use it, to clone github repo and use it through workflows scaffolder action.

The only problem I have right now is that I don't know how should we approach github app accept file, any ideas?

[aszarama]

Hey @shawnburke, figured out how to deal with scaffolder. Turns out we just have to handle two requests to the github.

I was able to use it, to clone github repo and use it through workflows scaffolder action.

The only problem I have right now is that I don't know how should we approach github app accept file, any ideas?

Scratch that, I've added custom header to all scaffolder requests, so it's easy to filter against.

It's all tested, working without a problem.

I've put my notes on how I wanted to handle things in this PR here: https://github.com/cortexapps/brain-backend/pull/11998

Any thoughts @shawnburke? Can we go live with this approach? (after adding app config too)

[shawnburke]

Please rebase on top of #57 and use the defaults so we don't break existing github axon users.

[aszarama]

I've cleaned up this PR. Here's what we want users to set:

• GITHUB - defaults to 'github.com'
• GITHUB_TOKEN - installation access token for github app, based on this: https://docs.github.com/en/apps/creating-github-apps/authenticating-with-a-github-app/authenticating-as-a-github-app-installation#about-authentication-as-a-github-app-installation

So for github token auth, there's GITHUB env, and for github app we have to set GITHUB and GITHUB_TOKEN.

[shawnburke]

looks good!