CI: Replace Flake8 with Ruff and use Alpine Edge instead of latest stable
See similar patch in pmbootstrap for rationale: https://gitlab.com/postmarketOS/pmbootstrap/-/commit/27618d5ffdb0b6cbf9471dc01a2ed14e1655ced0
W504 ignore is removed as the rule does not exist in Ruff. But, since it was ignored anyway, this does not matter.
Switching to Alpine Edge is necessary as Ruff only is available in testing for now. I created an issue about this upstream: https://gitlab.alpinelinux.org/alpine/aports/-/issues/15693
Edited by Administrator