fix tqdm import for download progress

Author: sberan

roboflow/models/object_detection.py

@@ -10,7 +10,7 @@
 import cv2
 import numpy as np
 import requests
-import tqdm
+from tqdm import tqdm
 from PIL import Image
 
 from roboflow.config import API_URL, OBJECT_DETECTION_MODEL, OBJECT_DETECTION_URL