Create annotations using stdout to avoid GITHUB_TOKEN

[ysbaddaden]

Extract from external discussion:

You can create annotations manually by writing some specific markup to stdout

crystal-lang/crystal#14608 (comment)

This mechanism was developed before the capability to create annotations using stdout messages was introduced.

crystal-lang/crystal#14608 (comment)

[straight-shoota]

I believe there must be another way to create annotations attached to code locations in a more structured manner without writing markup to stdout.
I don't recall how exactly. It might be related to junit output. We configure that it multiple workflows in https://github.com/crystal-lang/crystal/tree/master/.github/workflows (junit_output=.junit/xxx_spec.xml). So maybe GHA picks up the spec results in the .junit folder? I haven't found anything specific about this in the documentation.

[nobodywasishere]

It shouldn't be too hard to add an output format that matches the format needed for CI, that could be used by this github action to provide what's needed.