feat: configurable php versions

[michalsn]

Description
This PR introduces the ability to configure PHP versions across multiple reusable workflow templates.

All workflows now accept a php-versions or php-version input (depending on a workflow template), which allows users to override the default PHP versions used during workflow run. The default values remain unchanged, so existing workflows will continue to work without modification.

To customize the PHP versions in your project, you can now pass the input like this:

jobs:
  example:
    uses: codeigniter4/.github/.github/workflows/example.yml
    with:
      php-versions: '["8.2", "8.4"]'  # Use this for workflows that support multiple PHP versions (matrix)
      # php-version: '8.2'            # Use this if the workflow supports only a single PHP version

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[paulbalandan]

Just wondering, instead of having the matrix in the reusable workflows, why not have the calling workflows define the matrix strategy? It still feels off to me to write the matrix in pure string. It's counterintuitive to what we do normally with the matrix.

For reference, look at the main repo for the test-phpunit and its underlying reusable workflow.

[michalsn]

Hmm... yes, that would probably be a much better approach - but it would introduce a BC break.

The question is: do we care about backward compatibility in this case or not?
I've never actually asked this before, but is this repo intended for internal use only, or is it also meant for external/public use?

From what I understand, kenjis started branch CI45 for compatibility. Then I continued with CI46 to support the current version of the framework (change of PHP versions and dependencies), while we're still maintaining the main branch as well.

So I'm not against making changes - I just want to make sure we're on the same page about how things are supposed to work.

[paulbalandan]

From what I know and I asked chatgpt to confirm, files defined in this repo can also be used by other repos within the same org. So, this is for internal use only.

[michalsn]

Okay, I will try to come back with an improved version as you suggested - maybe tomorrow.