Update links to gitlab

.gitmodules

@@ -1,12 +1,12 @@
 [submodule "openlibm"]
 	path = openlibm
-	url = https://github.com/redox-os/openlibm.git
+	url = https://gitlab.redox-os.org/redox-os/openlibm.git
 [submodule "cbindgen"]
 	path = cbindgen
-	url = https://github.com/redox-os/cbindgen.git
+	url = https://gitlab.redox-os.org/redox-os/cbindgen.git
 [submodule "ralloc"]
 	path = ralloc
-	url = https://github.com/redox-os/ralloc.git
+	url = https://gitlab.redox-os.org/redox-os/ralloc.git
 [submodule "va_list"]
 	path = va_list
-	url = https://github.com/redox-os/va_list-rs.git
+	url = https://gitlab.redox-os.org/redox-os/va_list-rs.git