Updated code for Tensorflow 2.5 and CUDA 11.3

[Atif-Anwer]

Updated requirements:

The code was updated and last tested scuessfully with the following updated packages:

Tensorflow: 2.5.0
Keras: 2.4.3
OpenCV: 4.5.1
Numpy: 1.20.3 (also tried 1.19.2)
Python: 3.8.5
OS: Ubuntu 20.04 LTS

The training works on the following nvidia drivers:

NVIDIA Driver Version: 465.19.01
CUDA Version: 11.3
cuDNN Version: 8.1.1

NOTE: You can skip merging the readme.md since i changed it for myself.