DLR-RM/stable-baselines3: v2.8.0: Dropped Python 3.9, added Python 3.13 support, MaskablePPO bug fix, default hyperparams for unlisted env in the RL Zoo, Markdown doc

Breaking Changes: Removed support for Python 3.9, please upgrade to Python >= 3.10 Set strict=True for every call to zip(...) Switched to pygame-ce when installing extras New Features: Added official support for Python 3.13 Bug Fixes: Fixed saving and loading of Torch compiled models (using th.compile()) by updating get_parameters() Added a warning to env-checker if a multidiscrete space has multi-dimensional array (@unexploredtest) Fixed pandas.concat futurewarnings occuring when dataframes are empty by removing empty frames from the list before concatenating SB3-Contrib Set strict=True for every call to zip(...) Fixed MaskablePPO and RecurrentPPO inaccurate n_updates counting when target_kl early exits the training loop Fixed RecurrentPPO and MaskablePPO forward and predict not reshaping the action before clipping it (@immortal-boy) Do not call forward() method directly in RecurrentPPO (@immortal-boy) Fixed MaskableCategorical.apply_masking() crashing with ValueError: Simplex when cached probs deviate from sum=1 in float32 with large action spaces (torch 2.9+) (@kirann-05) Switched to Markdown documentation (using MyST parser) RL Zoo Set strict=True for every call to zip(...) Allow to specify env_kwargs in the hyperparam config Switched to Markdown documentation (using MyST parser) Allow to use default hyperparameters for any environment Save training command in Weights & Biases (Wandb) Save training command and default hyperparameters as study attributes SBX (SB3 + Jax) Increased Jax version range and use tf-nightly Deprecations: zip_strict() is not needed anymore since Python 3.10, please use zip(..., strict=True) instead Others: Updated to Python 3.10+ annotations Removed some unused variables (@unexploredtest) Improved type hints for distributions Simplified zip file loading by removing Python 3.6 workaround and enabling weights_only=True (PyTorch 2.x) Sped up saving/loading tests Updated black from v25 to v26 Updated monitor test to check handling of empty monitor files Documentation: Added a note on MultiDiscrete spaces with multi-dimensional arrays and a wrapper to fix the issue (@unexploredtest) Added an example of manual export of SBX (SB3 + Jax) model to ONNX (@m-abr) Switched to Markdown documentation (using MyST parser) New Contributors @unexploredtest made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2200 @m-abr made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2214 @sdace9719 made their first contribution in https://github.com/DLR-RM/stable-baselines3/pull/2218 Full Changelog: https://github.com/DLR-RM/stable-baselines3/compare/v2.7.1...v2.8.0