Added paths filter to GitHub actions

[iamdharmesh]

Description of the Change

This PR adds a paths filter in GitHub action workflows to run it only on specific file extensions. For example, This PR doesn't contain any PHP, JS, or CSS file changes. So, the related workflows(E2E tests, PHPUnit, PHPCS, PHP Compatibility, and ESLint) will not be run against this PR.

Closes #203

How to test the Change

See GitHub Actions check on this PR, E2E tests, PHPUnit, PHPCS, PHP Compatibility, and ESLint check should not run on this PR as we made changes in workflow files only.

Changelog Entry

Changed - Made GitHub Action workflow run only when required.

Credits

Props @iamdharmesh

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[peterwilsoncc]

Fake approval to see what happens.

Testing things and stuff

[peterwilsoncc]

Another fake approval to test things now that develop has been merged in.

Finished testing various things.

[peterwilsoncc]

Sorry for the review spam while I was testing the effects of this PR.

In its current state, it prevents merging of approved PRs as the required actions have not completed.

I think what you'll want to do is something like this (pseudo code)

step:
  Name: Succeed early if files are not modified
  run: |
    if ( no_relevant_file_modified() ) {
      finish_action_with_success();
    }

I'm not sure if that is possible though, it's something you'll need to check in the docs.

[iamdharmesh]

@peterwilsoncc we can handle this by adding a generic workflow that ignores the path we added to the actual workflow So, it will run instead of the actual workflow and we can satisfy the required condition. More info can be found here

I have created and added that workflow for PHPCS(c4d298d) and it works as expected. what do you think about this approach? If you think adding an additional dummy workflow for each required workflow is additional overhead then we might add path filters only on heavy workflows like E2E tests OR maybe adjust required workflow settings.

Thanks
cc: @dkotter

[peterwilsoncc]

Thank @iamdharmesh -- that looks like a really nice approach.

It does require repeating the paths in two files, so would need comments to alert people to change them in both locations. You could use a constant but I think that for two instances that would be over-engineering.

[peterwilsoncc]

LGTM with a minor nitpick inline.

I tested the changes with #209 to ensure that the tests run and fail as expected when needed.

[peterwilsoncc]

Thank you! LGTM.