libreoffice-collabora: use tag in update script

    rev=$(grep --perl-regexp --only-matching --max-count=1 \

        '\Krefs/tags/cp-\d+\.\d+\.\d+-\d+$' <<< "$all_tags")

    full_version=${rev#refs/tags/cp-}

    tag=${rev#refs/tags/}

    echoerr full version is $full_version

    echo \"$full_version\" > version.nix

        echo "{ fetchgit, ... }:" > $t.nix

        echo "fetchgit {" >> $t.nix

        echo "  url = \"$(jq -r '.url' <<< "$prefetch_output")\";" >> $t.nix

        echo "  rev = \"$rev\";" >> $t.nix

        echo "  tag = \"$tag\";" >> $t.nix

        echo "  hash = \"$(jq -r '.hash' <<< "$prefetch_output")\";" >> $t.nix

        echo "}" >> "$t.nix"

    done