Fix gym env following action changes.

Author: stepjam

rlbench/gym/rlbench_env.py

@@ -38,7 +38,7 @@ def __init__(self, task_class, observation_mode='state',
         _, obs = self.task.reset()
 
         self.action_space = spaces.Box(
-            low=-1.0, high=1.0, shape=(action_mode.action_size,))
+            low=-1.0, high=1.0, shape=(self.env.action_size,))
 
         if observation_mode == 'state':
             self.observation_space = spaces.Box(