fix[registration]: Address #256 by changing the path in the registrat…

…ion of the mujoco env.

urdfenvs/generic_mujoco/__init__.py

@@ -2,5 +2,5 @@
 from urdfenvs.generic_mujoco.generic_mujoco_env import GenericMujocoEnv
 register(
     id='generic-mujoco-env-v0',
-    entry_point='urdfenvs.urdf_common:GenericMujocoEnv'
+    entry_point='urdfenvs.generic_mujoco.generic_mujoco_env:GenericMujocoEnv'
 )