Remove blockers in requirements.txt

[onlinejudge95]

Can we remove the version blocker defined for keras and tensorflow in the requirements.txt?
All changes described here are in the master branch.
Since our GitHub action for build runs on python version 3.9 there are certain tests that will be failing. PR's affected by this is

• Updated name from lstm_prediction.py_tf to lstm_prediction.py and also imported keras #4422

There is already a PR #4374 for keras that handles this issue and is passing the checks