feat: support custom GitHub API base URL

[diogokiss]

GitHub Enterprise Server deployments require routing API calls to a custom endpoint instead of the default GitHub.com API.

This commit adds a new 'github_api_url' action input and passes it to Octokit as baseUrl so check run calls target the configured GitHub API host. Additionally, it documents the input in README and adds a test case that validates requests using /api/v3 when a custom API URL is provided.

[LouisBrunner]

Thanks a lot for your contribution, this is great. 😄

LGTM apart from a few minor changes.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[diogokiss]

Hey, @LouisBrunner ! Thank you for your review. I've addressed both of your suggestions/comments. The Pull Request is ready for another pass. 🤞🏼

[LouisBrunner]

🌟 Stellar! Thanks a lot for your contribution!!

[diogokiss]

🌟 Stellar! Thanks a lot for your contribution!!

Thank you for supporting open source software. 🫂

[frederikb]

@diogokiss did you test the latest version of action beforehand on GHES without your change? Because we've been using it for years on GHES without any problems.

checks-action/src/main.ts

Line 49 in 937cbbc

const octokit = github.getOctokit(inputs.token, {

The docs on the actions.getOctokit state the following:

Returns an authenticated Octokit client that follows the machine proxy settings and correctly sets GHES base urls

Source: https://github.com/actions/toolkit/blob/main/packages/github/README.md

which can be confirmed by verifying the implementation:

https://github.com/actions/toolkit/blob/b68d046fe39bcaf86bb49660cb3f307c35d6efb9/packages/github/src/internal/utils.ts#L42-L44

which uses the environment variable GITHUB_API_URL which in turn is documented as follows in the GHES docs:

Returns the API URL. For example: http(s)://HOSTNAME/api/v3.

Source: https://docs.github.com/en/enterprise-server@3.20/actions/reference/workflows-and-actions/variables#:~:text=the%20actor%20username.-,GITHUB_API_URL,-Returns%20the%20API