use different mujoco-py build options(under testing)

[Kallinteris-Andreas]

https://github.com/Kallinteris-Andreas/mujoco-py is a soft fork mujoco-py that simply changes the build flags

if this gets merged or a similar solution is found, we can delay #993

>>> import gymnasium
>>> import cython
>>> cython.__version__
'3.0.10'
>>> env = gymnasium.make("Ant-v2")
/home/master-andreas/temp/Gymnasium/gymnasium/envs/registration.py:518: DeprecationWarning: WARN: The environment Ant-v2 is out of date. You should consider upgrading to version `v5`.
  logger.deprecation(
/home/master-andreas/temp/Gymnasium/gymnasium/envs/mujoco/mujoco_py_env.py:217: DeprecationWarning: WARN: This version of the mujoco environments depends on the mujoco-py bindings, which are no longer maintained and may stop working. Please upgrade to the v5 or v4 versions of the environments (which depend on the mujoco python bindings instead), unless you are trying to precisely replicate previous works).
  logger.deprecation(

Advantages

• removes the requirement for cython <3

Downsides

• if the user runs pip gymnasium[mujoco-py] or pip gymnasium[all] with mujoco-py pre-installed, it will re-install mujoco-py potentially changing the version they had installed
• other unknown downsides I can not foresee

Alternatives

make a pypi package for this soft fork mujoc-py-updated???, but I would rather not do that

[pseudo-rnd-thoughts]

I would prefer to include this is as an "unofficial" solution such that we link to your repo / pypi for cython 3 but this is not the default solution