adds codecov token

Author: billbrod

.github/workflows/ci.yml

@@ -81,6 +81,8 @@ jobs:
         coverage xml -o ../coverage.xml
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@a079530fc142d3d288ddf76321ca0b7fe5b18df5 # v4.4.1
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
   all_tutorials_in_docs:
     runs-on: ubuntu-latest
     name: Check that all tutorial notebooks are included in docs