test-pypi-release job fails to push to test pypi (403 status)

👓 What did you see?

403 returned when pushing release 3.3.1 to https://test.pypi.org/project/ucam-identitylib/ from job in main branch pipeline:

https://gitlab.developers.cam.ac.uk/uis/devops/iam/identity-lib/-/jobs/1500933

✅ What did you expect to see?

Success status code, and release 3.3.1 appearing at https://test.pypi.org/project/ucam-identitylib/.

That's because no notable CI/CD changes have occurred between now and the last successful push to test-pypi-release 4 months ago: https://gitlab.developers.cam.ac.uk/uis/devops/iam/identity-lib/-/jobs/1289660

💻 Where does this happen?

🔬 How do I recreate this?

1. Ensure that you are using the same CI/CD variables at the time when pipeline #534917 (should be implicitly guaranteed)
2. Run the test_pypi_release job in the pipeline corresponding with the job above

📚 Any additional information?

Smells like it could be a problem with twine version? (not currently pinned)

Twine changelog: https://twine.readthedocs.io/en/latest/changelog.html