Switch to Github codecov action v2

.github/workflows/coverage.yml

@@ -33,7 +33,7 @@ jobs:
           coverage report
           coverage xml
       - name: Upload coverage to codecov
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v2
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           file: ./test/coverage.xml