Use dotty-staging forks for community build projects

`jackson-module-scala` and `scala-java-compat` were inadvertently
added using the upstream repository URLs

Author: griggt

.gitmodules

@@ -209,7 +209,7 @@
 	url = https://github.com/dotty-staging/libretto.git
 [submodule "community-build/community-projects/jackson-module-scala"]
 	path = community-build/community-projects/jackson-module-scala
-	url = https://github.com/FasterXML/jackson-module-scala.git
+	url = https://github.com/dotty-staging/jackson-module-scala.git
 [submodule "community-build/community-projects/scala-java8-compat"]
 	path = community-build/community-projects/scala-java8-compat
-	url = https://github.com/scala/scala-java8-compat.git
+	url = https://github.com/dotty-staging/scala-java8-compat.git