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',