fix: Set up version agnostic pk3 copy path

Author: SteveParson

Diff for: docker-containers/xonotic/clean.sh

@@ -6,8 +6,8 @@ rm -rf ./Xonotic-clean
 mkdir -p ./Xonotic-clean/data
 
 cp ./Xonotic/xonotic-linux64-dedicated ./Xonotic-clean
-cp ./Xonotic/data/xonotic-20170401-data.pk3 ./Xonotic-clean/data
-cp ./Xonotic/data/xonotic-20170401-maps.pk3 ./Xonotic-clean/data
-cp ./Xonotic/data/xonotic-20170401-nexcompat.pk3 ./Xonotic-clean/data
+cp ./Xonotic/data/xonotic-*-data.pk3 ./Xonotic-clean/data
+cp ./Xonotic/data/xonotic-*-maps.pk3 ./Xonotic-clean/data
+cp ./Xonotic/data/xonotic-*-nexcompat.pk3 ./Xonotic-clean/data
 
 echo "Copied data!"