Add Codecov CLI installation and coverage report upload to CI workflow

.github/workflows/ci.yml

@@ -1,4 +1,5 @@
 name: Tox CI with Conda
+# run locally with: act --container-architecture linux/amd64
 
 on:
   push:
@@ -64,7 +65,7 @@ jobs:
           conda init
           source ~/.bashrc
           conda activate test-env
-          pip install tox tox-conda
+          pip install tox tox-conda codecov codecov-cli
 
       - name: Install GCC and GFortran
         run: |
@@ -81,6 +82,7 @@ jobs:
           source ~/.bashrc
           conda activate test-env
           tox -e py$(echo ${{ matrix.python-version }} | tr -d . | cut -c 1-3)
+          codecov -t ${{ secrets.CODECOV_TOKEN }} -F unittests -n 'unittests'-${{ matrix.python-version }}-${{ github.run_id }}
 
       - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v5