fix export input name

ml-agents/mlagents/trainers/torch/model_serialization.py

         dummy_memories = torch.zeros(batch_dim + [1] + [self.policy.m_size])
 
         self.input_names = []
-        self.dynamic_axes = {"action": {0: 'batch'}, "action_probs": {0: 'batch'}}
+        self.dynamic_axes = {"action": {0: "batch"}, "action_probs": {0: "batch"}}
-            self.dynamic_axes.update({"vector_observation": {0: 'batch'}})
+            self.dynamic_axes.update({"vector_observation": {0: "batch"}})
-            self.dynamic_axes.update({"visual_observation": {0: 'batch'}})
+            self.dynamic_axes.update({"visual_observation": {0: "batch"}})
-            self.input_names.append("action_mask")
-            self.dynamic_axes.update({"action_mask": {0: 'batch'}})
+            self.input_names.append("action_masks")
+            self.dynamic_axes.update({"action_masks": {0: "batch"}})
-            self.dynamic_axes.update({"memories": {0: 'batch'}})
+            self.dynamic_axes.update({"memories": {0: "batch"}})
 
         self.output_names = [
             "action",