Fix dependencies setup

[saahil-mahato]

Problem:
Currently only the main dependencies are mentioned in the setup tools. This is bad because the nested dependencies' latest version are installed by default. This creates compatibility issues and the program throws a runtime error when following instructions in Readme.me

Proposed solution:

1. Create a separate requirements.txt and requirements-dev.txt file that includes list and versions of all dependencies and also update the packages to latest version available for python 3.8.
2. Refactor code to remove deprecated functions and resolve all warnings.