[chore] Add flake8 workflow

[Aryamanz29]

Description

Added workflow for Flake8

Fixes #226

Type of Change:

• Code
• Quality Assurance

How Has This Been Tested?

Tested on Github.

Fail : https://github.com/Aryamanz29/bridge-in-tech-backend/actions/runs/728480082 Success : https://github.com/Aryamanz29/bridge-in-tech-backend/actions/runs/728482243

Checklist:

• [x] My PR follows the style guidelines of this project
• [x] I have performed a self-review of my own code or materials

Code/Quality Assurance Only

• [x] My changes generate no new warnings
• [ ] My PR currently breaks something (fix or feature that would cause existing functionality to not work as expected)
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been published in downstream modules

[Aryamanz29]

Please don't review this PR, I'm still working on this. I'll ping maintainers soon after fixing tests.

[devkapilbansal]

@Aryamanz29 you can mark a pull request as draft if it is not ready for review. Btw, thanks for letting us know that this PR is still in progress

[Aryamanz29]

@devkapilbansal While testing my code locally most unittest fails and I'm unable to debug it after several attempts, So kindly unassign this issue to me for now. I'll try to work on this issue later.

[mtreacy002]

@Aryamanz29 , have you completed the local setup #244 as requested here? If so, can you submit a pr showing the gif in the pr description as requested on the tasks?

[mtreacy002]

Unassigning as per contributor's request [here]https://github.com/anitab-org/bridge-in-tech-backend/pull/260#issuecomment-816832563).