Flagged Out-of-Date Comment: slirp4netns-git

xiota flagged slirp4netns-git out-of-date on 2023-10-24 (UTC) for the following reason:

`pkgver()` needs to be updated, in accordance with VCS package guidelines. Also: Remove unnecessary `|| exit 1` statements. Don't install license file because GPL2 is in `/usr/share/licenses/common`. Would be beneficial to compare and resync with `extra/slirp4netns`.