PHPCS formatting automated

• This GitHub Action automates PHPCS formatting across your project, ensuring consistent code styling by creating a new branch for review when necessary. It simplifies integrating PHPCS/PHPCBF into your workflow.
• A warning appears in the GitHub Actions Annotations section if changes occur and therefore a new branch is created.
• A proposed manual changed linked from the warning in the GitHub Actions Annotations section.
• The input parameter commit-changes: true to commit to the current branch.
• Customizable Commit Message: Introduced an input commit-message to allow users to specify a custom commit message.
• Branch Name Output: The branch-name is provided as an output for downstream workflows.
• Notice about a successful commit.
• Checkout code: Fetches the latest changes so that modifications from a previous job are included, enabling seamless job chaining.
• The new boolean input stop-on-manual-fix will cause the workflow to stop (fail) if manual fixes are necessary. (Also stops with an error if some manual fixes are required on top of automatic fixes.)
• Cached vendor/ (for a unique combination of php-version and composer.json) after a successful run in order to speed up further runs.