MeltingPot examples do not work

[jagapiou]

The examples need to be updated to ensure they can run.

Currently there are dependency conflicts in the MeltingPot examples/requirements.txt

stable-baselines3 2.2.1 requires gymnasium<0.30,>=0.28.1, but you have gymnasium 0.26.3 which is incompatible.
supersuit 3.9.2 requires gymnasium>=0.28.1, but you have gymnasium 0.26.3 which is incompatible.
pettingzoo 1.24.3 requires gymnasium>=0.28.0, but you have gymnasium 0.26.3 which is incompatible.

No workaround right now, sorry.