pmbootstrap 3.11 is strict-by-default and previous versions had a broken
implementation which broke upon a full bootstrap of e.g. the systemd
repo. I think it's therefore safe to remove this already, even without
bumping pmbootstrap_min_version.
[ci:skip-vercheck]: doesn't affect any artifacts
Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/9112>