Reduce `opencv-python>=4.1.1` for Jetson Nano (#7645)

May help https://github.com/ultralytics/yolov5/issues/7631#issuecomment-1113007451

requirements.txt

@@ -3,7 +3,7 @@
 # Base ----------------------------------------
 matplotlib>=3.2.2
 numpy>=1.18.5
-opencv-python>=4.1.2
+opencv-python>=4.1.1
 Pillow>=7.1.2
 PyYAML>=5.3.1
 requests>=2.23.0