Support `.clang-tidy` out of the box

[vadi2]

It's common to have a .clang-tidy file at the root of the repo (hundred of repos on github), what about supporting it out of the box so the file is read first if found, otherwise it uses the explicit list of checks?

This is coming from the perspective that this is unnecessary scaffolding that we can do without -

      uses: ZedThree/clang-tidy-review@v0.8.1
      with:
        config_file: '.clang-tidy'

[vadi2]

Sweet, thanks for covering this.