Fix PettingZoo's implicit required dependency

ai_traineree/__init__.py

@@ -1,7 +1,7 @@
 import numpy
 import torch
 
-__version__ = "0.3.3"
+__version__ = "0.3.4"
 
 
 # This is expected to be safe, although in PyTorch 1.7 it comes as a warning,

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = ai-traineree
-version = 0.3.3
+version = 0.3.4
 author = Dawid Laszuk
 author_email = [email protected]
 description = Yet another zoo of (Deep) Reinforcment Learning methods in Python using PyTorch
@@ -36,14 +36,14 @@ test =
     pytest-mock~=3.3
     flake8~=3.9
     gym[box2d]~=0.19.0
-    pettingzoo[sisl]==1.8.*
+    pettingzoo[sisl,other]==1.11.*  # `other` is needed because PettingZoo requires but doesn't add pillow
 # Loggers
 tensorboard = tensorboard
 neptune = neptune-client; psutil
 # Envs
 gym = gym[all]==0.19.0
 mlagents = mlagents
-pettingzoo = pettingzoo==1.8.*
+pettingzoo[other] = pettingzoo==1.11.0  # `other` is needed because PettingZoo requires but doesn't add pillow
 examples =
     matplotlib
     tensorboard