Use codecov action.

Author: tobiasraabe

.github/workflows/main.yml

@@ -59,16 +59,16 @@ jobs:
         shell: bash -l {0}
         run: tox -e test -- tests -m "unit or (not integration and not end_to_end)" --cov=src --cov=tests --cov-report=xml
 
-      - name: Upload coverage report for unit tests and doctests.
-        if: runner.os == 'Linux' && matrix.python-version == '3.10'
-        shell: bash -l {0}
-        run: bash <(curl -s https://codecov.io/bash) -F unit -c
+      - name: Upload unit test coverage reports to Codecov with GitHub Action
+        uses: codecov/codecov-action@v4
+        with:
+          flags: unit
 
       - name: Run end-to-end tests.
         shell: bash -l {0}
         run: tox -e test -- tests -m end_to_end --cov=src --cov=tests --cov-report=xml
 
-      - name: Upload coverage reports of end-to-end tests.
-        if: runner.os == 'Linux' && matrix.python-version == '3.10'
-        shell: bash -l {0}
-        run: bash <(curl -s https://codecov.io/bash) -F end_to_end -c
+      - name: Upload end_to_end test coverage reports to Codecov with GitHub Action
+        uses: codecov/codecov-action@v4
+        with:
+          flags: end_to_end