[PRQ#71375] Merge Request for git-credential-manager-core

ItachiSan [1] filed a request to merge git-credential-manager-core [2] into git-credential-manager [3]: I've created `git-credential-manager` since the upstream rename and maintained ever since. I believe people had enough time to migrate. If necessary, I can make a patch release with some message hinting to migrating to the new package. [1] https://aur.archlinux.org/account/ItachiSan/ [2] https://aur.archlinux.org/pkgbase/git-credential-manager-core/ [3] https://aur.archlinux.org/pkgbase/git-credential-manager/