Migrate from docker to composite run actions

[mgrachev]

Links:

• https://github.blog/changelog/2020-08-07-github-actions-composite-run-steps
• https://docs.github.com/en/actions/creating-actions/creating-a-composite-run-steps-action

Inspiration:

• https://github.com/reviewdog/action-golangci-lint/pull/46
• https://github.com/reviewdog/action-tflint/pull/28

[adnikiforov]

Gotta take a look at this one 👁️

[mgrachev]

I have already migrated action-reek. You can take this as an example.