Add codecov token

Author: jluethi

.github/workflows/ci_pip.yml

@@ -46,4 +46,7 @@ jobs:
         run: pytest --color=yes --cov --cov-report=xml --cov-report=term-missing -s --log-cli-level debug
 
       - name: Upload coverage reports to Codecov
-        uses: codecov/[email protected]
+        uses: codecov/[email protected]
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          slug: jluethi/fractal-helper-tasks