Point munit to dotty-staging fork

Author: gabro

.gitmodules

@@ -70,4 +70,4 @@
 	url = https://github.com/ekrich/sconfig.git
 [submodule "community-build/community-projects/munit"]
 	path = community-build/community-projects/munit
-	url = https://github.com/scalameta/munit.git
+	url = https://github.com/dotty-staging/munit.git