add Python 3.15.0-rc.2

[semuadmin]

sandpit Pull Request Template

Description

1. Add Python 3.15.0-beta to workflows.

Testing

Please test all changes, however trivial, against the supplied pytest suite tests/test_*.py. Please describe any test cases you have amended or added to this suite to maintain >= 99% code coverage.

• Test A
• Test B

Checklist:

• I agree to abide by the code of conduct (see CODE_OF_CONDUCT.md).
• My code follows the style guidelines of this project (see CONTRIBUTING.MD).
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• (if appropriate) I have added test cases to the tests/test_*.py unittest suite to maintain >= 99% code coverage.
• I have tested my code against the full tests/test_*.py unittest suite.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I have signed my commits.
• I understand and acknowledge that the code will be published under a BSD 3-Clause license.