Merge pull request #291 from dora-rs/fix-yolov5-dependency-issue

Fix yolov5 dependency issue

examples/python-dataflow/requirements.txt

@@ -2,6 +2,7 @@
 # Usage: pip install -r requirements.txt
 
 # Base ----------------------------------------
+ultralytics
 gitpython
 ipython  # interactive notebook
 matplotlib>=3.2.2

examples/python-operator-dataflow/requirements.txt

@@ -2,6 +2,7 @@
 # Usage: pip install -r requirements.txt
 
 # Base ----------------------------------------
+ultralytics
 matplotlib>=3.2.2
 numpy>=1.18.5
 opencv-python>=4.1.1
@@ -43,4 +44,4 @@ thop>=0.1.1  # FLOPs computation
 # roboflow
 
 opencv-python>=4.1.1
-pyarrow
+pyarrow