use .tar.xz for archived of git repos in Cargo easyblock#8

Flamefire merged 2 commits intoFlamefire:20250305174305_new_pr_cargoFlamefire/easybuild-easyblocks:20250305174305_new_pr_cargofrom

lexming:fix-git-repos-cargolexming/easybuild-easyblocks:fix-git-repos-cargoCopy head branch name to clipboard