add hub version check

paddlex/__init__.py

@@ -26,6 +26,11 @@ except:
     print("[WARNING] pycocotools is not installed, detection model is not available now.")
     print("[WARNING] pycocotools install: https://github.com/PaddlePaddle/PaddleX/blob/develop/docs/install.md")
 
+import paddlehub as hub
+if hub.version.hub_version < '1.6.2':
+    raise Exception("[ERROR] paddlehub >= 1.6.2 is required")
+
+
 env_info = get_environ_info()
 load_model = cv.models.load_model
 datasets = cv.datasets