Add Codecov token to GitHub Actions workflow for authenticated coverage uploads

Author: Ray-Gee

.github/workflows/coverage.yml

@@ -28,4 +28,5 @@ jobs:
       uses: codecov/codecov-action@v3
       with:
         file: ./lcov.info
-        fail_ci_if_error: true 
+        fail_ci_if_error: true
+        token: ${{ secrets.CODECOV_TOKEN }}