text: Title: Sweep: add test coverage badge to github project
  Body: 
  
  
  <details open>
  <summary>Checklist</summary>
  
  - [X] `.github/workflows/python-app.yml`
  > • Add a new step to run tests with coverage using pytest-cov. This step should be added after the step where the tests are currently being run.
  > • In the new step, use the command `pytest --cov=./` to run the tests with coverage.
  > • Add another step to send the coverage report to Codecov. This can be done using the codecov/codecov-action GitHub Action. The step should look like this:
  >   - name: Upload coverage to Codecov
  >     uses: codecov/codecov-action@v1
  
  - [X] `README.md`
  > • Add the Codecov badge to the top of the README file. The markdown for the badge can be obtained from the settings page of the repository on Codecov. It should look something like this: `[![codecov](https://codecov.io/gh/AntonOsika/gpt-engineer/branch/main/graph/badge.svg?token=YOURTOKEN)](https://codecov.io/gh/AntonOsika/gpt-engineer)`
  
  </details>
  