Attempt upgrading codecov action to see if tokenless uploads can be made to work

.github/workflows/ci.yml

@@ -41,9 +41,10 @@ jobs:
         run: |
           pytest --cov=meshtastic --cov-report=xml
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v2
+        uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+          env_vars: OS, PYTHON
           files: ./coverage.xml
           flags: unittests
           name: codecov-umbrella