ci: bump codecov/codecov-action from 1 to 2.1.0

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/coverage.yml

@@ -27,5 +27,5 @@ jobs:
           args: '--all-features'
 
       - name: Upload to codecov.io
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v2.1.0