Bump codecov/codecov-action from v1.2.2 to v1.3.1 (#237)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from v1.2.2 to v1.3.1.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/master/CHANGELOG.md)
- [Commits](codecov/codecov-action@v1.2.2...fcebab0)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
         run: pytest --cov=twentemilieu --cov-report=xml
       - name: Upload coverage to Codecov
         if: matrix.python == 3.8 && matrix.os == 'ubuntu'
-        uses: codecov/codecov-action@v1.2.2
+        uses: codecov/codecov-action@v1.3.1
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           file: ./coverage.xml