ci(actions): bump codecov/codecov-action from v6 to v7

- Update codecov/codecov-action GitHub Action from v6 to v7

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: appleboy

.github/workflows/go.yml

@@ -61,6 +61,6 @@ jobs:
           go test -v -covermode=atomic -coverprofile=coverage.out
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@v7
         with:
           flags: ${{ matrix.os }},go-${{ matrix.go }}