change moreglass submodule to relative url to avoid workaround in runner

.gitmodules

@@ -298,7 +298,7 @@
 	url = ../../Illuna-Minetest/skybox
 [submodule "mods/moreglass"]
 	path = mods/moreglass
-	url = ssh://git@git.tchncs.de:2241/Illuna-Minetest/moreglass.git
+	url = ../../Illuna-Minetest/moreglass.git
 [submodule "mods/hbsprint"]
 	path = mods/hbsprint
 	url = https://github.com/minetest-mods/hbsprint