Add “merge” and “upstream” entries for submodules.

.gitmodules

@@ -1,18 +1,33 @@
 [submodule "pegtl"]
 	path = include/lol/3rdparty/pegtl
-	url = ../../lolengine/ext-pegtl.git
+	url = https://github.com/lolengine/ext-pegtl
 	branch = lol
+	update = merge
+	upstream = https://github.com/taocpp/PEGTL
+
 [submodule "mingw-std-threads"]
 	path = include/lol/3rdparty/mingw-std-threads
-	url = ../../lolengine/ext-mingw-std-threads.git
+	url = https://github.com/lolengine/ext-mingw-std-threads
 	branch = master
+	update = merge
+	upstream = https://github.com/meganz/mingw-std-threads
+
 [submodule "step"]
 	path = include/lol/3rdparty/step
-	url = ../../lolengine/ext-step
+	url = https://github.com/lolengine/ext-step
+	branch = lol
+	update = merge
+	upstream = https://github.com/storm-ptr/step
+
 [submodule "portable-file-dialogs"]
 	path = include/lol/3rdparty/portable-file-dialogs
-	url = ../../samhocevar/portable-file-dialogs.git
+	url = https://github.com/samhocevar/portable-file-dialogs
 	branch = master
+	update = merge
+
 [submodule "cli11"]
 	path = include/lol/3rdparty/cli11
-	url = ../../lolengine/ext-cli11.git
+	url = https://github.com/lolengine/ext-cli11
+	branch = lol
+	update = merge
+	upstream = https://github.com/CLIUtils/CLI11