Add TWINE_USERNAME and TWINE_PASSWORD to group CI/CD settings
While working on #8 (closed), I've identified a way to pass credentials to twine and upload the dists. However, for the process to work, PyPI credentials need to be supplied.
Unlike Travis CI, GitLab CI does not have support for encrypted variables (variables encrypted on an individual's computer decryptable only using a key private to the repository that's inaccessible even to the devs on the project).
Instead, GitLab CI has secret variables, which provide some level of secrecy, but are readily exposed to other members with the same access.
I have access to configure these variables for importlib_metadata
but probably not for other projects in python-devs, which is probably where these credentials should be installed.
While working out this ticket, I found some really buggy behavior on that page. In fact, I think I was able to access that page even though I'm possibly not supposed to be (I can't see the menu, but I can set and retrieve values, if I first navigate through another group where I have access).