chore(retentions): add new retentions method for support drafts

[raul-facturapi]

No description provided.

[Copilot]

Pull request overview

This PR introduces support for working with draft retentions in the PHP SDK, adding dedicated draft lifecycle methods and adjusting cancellation behavior to support deleting draft retentions. It also adds PHPUnit coverage to validate the generated HTTP requests for these new/updated behaviors.

Changes:

• Add Retentions::updateDraft(), Retentions::copyToDraft(), and Retentions::stampDraft(), plus deprecated snake_case aliases for backward compatibility.
• Allow Retentions::cancel() to be called without query parameters (enables deleting draft retentions via a plain DELETE).
• Add PHPUnit tests verifying request methods, URLs, and payloads for draft retention flows.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
VERSION.md	Documents the new 4.6.0 SDK changes related to draft retentions.
tests/Resources/RetentionsTest.php	Adds request-level tests for draft retention creation, update, copy, stamp, cancellation, and filtering.
src/Resources/Retentions.php	Implements draft retention methods and makes cancel() query optional; adds deprecated snake_case aliases.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.