Fix typo in gym-unity doc (#4937)

Corrected Çhange to Change in the docs.

gym-unity/README.md

 def main():
     unity_env = UnityEnvironment("./envs/GridWorld")
     env = UnityToGymWrapper(unity_env, 0, uint8_visual=True)
-    logger.configure('./logs') # Çhange to log in a different directory
+    logger.configure('./logs') # Change to log in a different directory
     act = deepq.learn(
         env,
         "cnn", # conv_only is also a good choice for GridWorld