Automatically Sync Stubs with PHP Storm

[mnavarrocarter]

Context

We want stubs for this extension to be present in PHP Storm default stubs distribution, so users can easily discover the available symbols.

Proposal

Automate the process of preparing a pull request to the PHPStorm stubs repository.

Acceptance Criteria

• On every push to main, we run a workflow that creates a pull request to this repository only if the file changes
• The stubs file is placed under identifier/ folder, named as identifier.php.
• The commit message references the original commit in the php-ext-identifier repository and preserves the author