devel/py-python-gitlab: Update to 3.13.0

ChangeLog: https://github.com/python-gitlab/python-gitlab/releases/tag/v3.13.0

Feature

• group: Add support for group restore API
• client: Automatically retry on HTTP 409 Resource lock
• api: Add support for bulk imports API
• api: Add support for resource groups
• api: Support listing pipelines triggered by pipeline schedules
• Allow filtering pipelines by source
• client: Bootstrap the http backends concept
• Add resource iteration events
• Allow passing kwargs to Gitlab class when instantiating with from_config
• Add keep_base_url when getting configuration from file

Fix

• client: Regression - do not automatically get_next if page=# and
• Change return value to "None" in case getattr returns None to prevent error
• deps: Bump requests-toolbelt to fix deprecation warning
• Use the ProjectIterationManager within the Project object
• api: Make description optional for releases

Documentation

• faq: Describe and group common errors

PR: 269331
Reported by: dereks@lifeofadishwasher.com (maintainer)