Separate the conflict solving section, and upgrade atari_py

environment.yml

@@ -3,7 +3,7 @@ channels:
   - conda-forge
   - defaults
 dependencies:
-  - atari_py=0.2.6  # used only in chapter 17
+  - atari_py=0.2  # used only in chapter 17
   - box2d-py=2.3  # used only in chapter 17
   - ftfy=6.0  # used only in chapter 15 by the transformers library
   - graphviz  # used only in chapter 5 for dot files
@@ -46,6 +46,8 @@ dependencies:
     - tfx~=1.3.0  # platform to deploy production ML pipelines
     - transformers~=4.11.3  # Natural Language Processing lib for TF or PyTorch
     - urlextract~=1.4.0  # optionally used in chapter 3, exercise 4
+
+# Specific lib versions to avoid conflicts
   - attrs=20.3
   - click=7.1
   - packaging=20.9