⬆️ Bump codecov-action to v3 + fix CI (#29)

Author: hayesall

.github/workflows/python-package.yml

@@ -43,8 +43,9 @@ jobs:
       run: |
         pytest --cov=relational_datasets/ --cov-report=xml relational_datasets/
     - name: Upload reports to Codecov
-      uses: codecov/codecov-action@v2
+      uses: codecov/codecov-action@v3
       with:
+        token: ${{ secrets.CODECOV_TOKEN }}
         env_vars: OS,PYTHON
         fail_ci_if_error: true
         files: ./coverage.xml