These issues were caused by type annotations introduced in 4e0331f2.
In 96f36723, the fallout was partially fixed in `licensepkg.py` but not
the rest of the codebase.

Fix the issue for all occurrences I could spot.
I mainly inspected all `arg-type` violations, but I also fixed other
occurrences that mypy can’t detect yet whenever I bumped into one.

CC: David Runge <dvzrv@archlinux.org>