Reactivate coverage badge action

[jobrachem]

Once the following issue is fixed, we can reactivate the coverage badge action:

• https://github.com/tj-actions/coverage-badge-py/issues/163

Then, the following code can be added again to the pytest action:

      - name: Create coverage badge
        uses: tj-actions/coverage-badge-py@v2
        with:
          output: coverage-new.svg

      - name: Commit coverage.svg
        run: |
          git config --local user.name "github-actions[bot]"
          git config --local user.email "github-actions[bot]@users.noreply.github.com"
          git ls-remote | grep refs/heads/pytest-cov && git remote set-branches --add origin pytest-cov && git fetch
          git switch pytest-cov || git switch --orphan pytest-cov
          mv coverage-new.svg coverage.svg
          git add coverage.svg
          git diff --staged --quiet || git commit -m "Updated coverage.svg"

      - name: Push coverage.svg
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: pytest-cov