Update all non-sr.ht Python packages

py3-gitlab: add py3-requests-toolbelt dependency

py3-gitlab: upgrade to 2.7.1

py3-gitlab: bump pkgrel

py3-gitlab: re-introduce package

This package was removed for being "upstream" in Alpine, but it does not
actually appear to be.

Drop obsolete & upstreamed packages

py3-gitlab: upgrade to 2.2.0

sr.ht/py3-gitlab: upgrade to 1.15.0

Add py3-gitlab package