[RLlib](deps): Bump atari-py in /python/requirements/rllib

Bumps [atari-py](https://github.com/openai/atari-py) from 0.2.6 to 0.2.9.
- [Release notes](https://github.com/openai/atari-py/releases)
- [Commits](openai/atari-py@0.2.6...0.2.9)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

python/requirements/rllib/requirements_rllib.txt

@@ -14,7 +14,7 @@ torchvision==0.9.1+cpu;sys_platform!="darwin"
 # Environment adapters.
 # ---------------------
 # Atari
-atari_py==0.2.6
+atari_py==0.2.9
 gym[atari]==0.18.0
 # Kaggle envs.
 kaggle_environments==1.7.11