Correctly pass tensor to device

According to the docs, input_tensor.to(device) doesn't move the tensor to the device but returns a tensor that's on the device.

Fixes GPU predictions

dan/predict/prediction.py

@@ -100,7 +100,7 @@ class DAN:
         :param confidences: Return the characters probabilities.
         :param attentions: Return characters attention weights.
         """
-        input_tensor.to(self.device)
+        input_tensor = input_tensor.to(self.device)
 
         start_token = len(self.charset) + 1
         end_token = len(self.charset)