Update .gitmodules

.gitmodules

 [submodule "src/franka_description"]
 	path = src/franka_description
-	url = ../../franka_description.git
+	url = ../franka_description.git
 [submodule "src/panda_moveit_config"]
 	path = src/panda_moveit_config
-	url = ../../panda_moveit_config.git
+	url = ../panda_moveit_config.git
 [submodule "src/panda_simulation"]
 	path = src/panda_simulation
-	url = ../../panda_simulation.git
+	url = ../panda_simulation.git
 [submodule "src/sample_applications"]
 	path = src/sample_applications
-	url = ../../sample_applications.git
+	url = ../sample_applications.git
 [submodule "src/panda_teaching"]
 	path = src/panda_teaching
-	url = ../../panda_teaching.git
+	url = ../panda_teaching.git