add weighted_lb feature

.github/workflows/test.yml

@@ -45,10 +45,10 @@ jobs:
     name: codecov
     runs-on: ubuntu-latest
     steps:
-      - name: Set up Go 1.15
+      - name: Set up Go 1.16
         uses: actions/setup-go@v3
         with:
-          go-version: 1.15.x
+          go-version: 1.16.x
         id: go
 
       - name: Checkout code