Compatibility Issues with tfv2 - C4 W4

[Raghav4138]

I was running the "Autonomous_driving_application_Car_detection_v3a.ipynb" file with tfv2.
But since, many functions have been deprecated in Tensorflow version 2, it was giving many errors.
I have found out and resolved some of them.

Also, yolo_anchors.txt file was not easily accessible. I would be great if you include it in the repo itself.

Note: Only the functions till "Summary for YOLO" have been updated. Functions beyond "3 - Test YOLO pre-trained model on images", have not been edited yet.

I will make a PR for the same.