[CI] Fix yourdfpy testenv

Author: stephane-caron

tox.ini

@@ -87,7 +87,7 @@ deps =
     trimesh ~=3.16.0
     yourdfpy >=0.0.53
 commands =
-    python -m unittest tests/loaders/test_yourdfpy.py
+    python -m unittest test_yourdfpy.py
 
 [pylint]
 generated-members=mujoco.MjModel, pin.JointModelFreeFlyer, pin.JointModelPX, pin.JointModelPY, pin.JointModelPZ, pin.JointModelPlanar, pin.JointModelRX, pin.JointModelRY, pin.JointModelRZ, pin.JointModelSpherical, pin.JointModelSphericalZYX, pin.JointModelTranslation, pin.Model, pybullet.loadURDF, pybullet.setAdditionalSearchPath