chore: 7.5.0 prep pr

[edmondchuc]

Summary of changes

RDFLib version 7.5.0 preparation PR.

The following small tasks need to be addressed before this PR is merged:

• - Merge docs: add RDF4J Store and Client user docs #3319
• - Update release date in this PR

Checklist

• Checked that there aren't other open pull requests for
  the same change.
• Checked that all tests and type checking passes.
• If the change adds new features or changes the RDFLib public API:
  • Created an issue to discuss the change and get in-principle agreement.
  • Considered adding an example in ./examples.
• If the change has a potential impact on users of this project:
  • Added or updated tests that fail without the change.
  • Updated relevant documentation to avoid inaccuracies.
  • Considered adding additional documentation.
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.