Support cuda

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

detectron.py

@@ -55,7 +55,7 @@ class Detectron2(NNOperator):
         res = self._predictor(image[:,:,::-1])
         res = res['instances']
         boxes = res.get('pred_boxes').tensor.cpu().numpy()
-        classes = res.get('pred_classes').numpy()
-        scores = res.get('scores').numpy()
+        classes = res.get('pred_classes').cpu().numpy()
+        scores = res.get('scores').cpu().numpy()
 
         return (boxes, classes, scores)