Allow reporting annotations without creating a new check

[nielsvanvelzen]

Right now this action adds a new check to report all annotations. Ideally I'd want to disable this behavior and just report annotations "normally" like other actions do.

For example, one of the linters I use is markdownlint and I enabled a problem matcher for that to create annotations. Another one is yutailang0119/action-android-lint that uses the GitHub actions toolkit to create the annotations from a Android XML file.

[jwgmeligmeyling]

Currently the Github API only allows pushing annotations by creating a new check run. I have asked Github to provide alternative APIs but as of now I have no clue how this could be done. More or less related to #2.

PRs are welcome :)

[nielsvanvelzen]

I took a better look at the android linter I mentioned and it simply said it prints the annotations to stdout via the command helper from the toolkit: https://github.com/actions/toolkit/blob/main/packages/core/src/command.ts

I'll see if I can make a PR for it later