MAJOR: Moving setup to default to Gymnasium. Last stable point is gym…

…=0.13. Feel free to revert back to this when facing instability due to gym versions

setup.py

@@ -50,7 +50,8 @@ def package_files(directory):
     author_email="[email protected]",
     install_requires=[
         'click',
-        'gym==0.13',
+        # 'gym==0.13',  # default to this stable point if caught in gym issues.
+        'gymnasium==0.29.1',
         'mujoco==3.1.3',
         'dm-control==1.0.16',
         'termcolor',