Update the git URL for the git snapshot script

And change to .xz since that's what we get from upstream.

libxkbcommon.spec

@@ -8,7 +8,7 @@ License:        MIT
 URL:            http://www.x.org
 
 %if 0%{?gitdate}
-Source0:       %{name}-%{gitdate}.tar.bz2
+Source0:       %{name}-%{gitdate}.tar.xz
 %else
 Source0:        http://xkbcommon.org/download/%{name}-%{version}.tar.xz
 %endif

make-git-snapshot.sh

@@ -3,7 +3,7 @@
 DIRNAME=libxkbcommon-$( date +%Y%m%d )
 
 rm -rf $DIRNAME
-git clone git://anongit.freedesktop.org/git/xorg/lib/libxkbcommon $DIRNAME
+git clone https://github.com/xkbcommon/libxkbcommon $DIRNAME
 cd $DIRNAME
 if [ -z "$1" ]; then
     git log | head -1
@@ -13,5 +13,5 @@ fi
 git log | head -1 | awk '{ print $2 }' > ../commitid
 git repack -a -d
 cd ..
-tar jcf $DIRNAME.tar.bz2 $DIRNAME
+tar Jcf $DIRNAME.tar.xz $DIRNAME
 rm -rf $DIRNAME