[CI] build arch linux package from the merge request branch

currently the arch linux package is build in CI from source that is obtained by clonning this repository and that fetches the main branch, instead for MR we need to build the package from the changes that are present in the MR branch.

since the CI job already clones the repository and checks out the merge request branch, we can use the local filesystem path as the source for the package, or a tar archive of the git repository. see https://wiki.archlinux.org/title/PKGBUILD#Sources

changed milestone to %2025.04 LEAP VPN Release

added packaging label

assigned to @peanut2

changed title from [CI] build arch linux package from the MR branch and not from main to [CI] build arch linux package from the merge request branch

mentioned in merge request !280 (merged)

unassigned @peanut2

removed milestone %2025.04 LEAP VPN Release