Action required: Add stable-2.13 to the test matrix

[Andersson007]

Dear maintainers,

According to the Collection requirements, collections included in the ansible package MUST run the ansible-test sanity command from the latest stable ansible-core branch.

It has been recently announced via the news-for-maintainers repository that the ansible-core stable-2.13 branch is available for testing.

• Please add the stable-2.13 branch to your test matrix in the .github/workflows directory, at least, in the sanity jobs section. Any questions, just mention me here.

• If you have integration and/or unit tests, please consider adding the branch to the corresponding sections too.

• If you're not subscribed to the news-for-maintainers repository, please do it to avoid CI related issues in the future.

• If the issue is not relevant to your collection, please close it.

Thank you!

[Andersson007]

closed via https://github.com/ansible-collections/community.cassandra/pull/216, @rhysmeister thanks!