fix(ci): pin golangci-lint to v2.1.6 to match local and support v2 config

'latest' resolves to v1.64.8 which doesn't support version: 2 config.
Pin to v2.1.6 to match local development environment and ensure
v2 config compatibility.

.github/workflows/ci.yml

@@ -81,7 +81,7 @@ jobs:
       - name: Run golangci-lint
         uses: golangci/golangci-lint-action@v3
         with:
-          version: latest
+          version: v2.1.6
           args: --timeout=5m
 
   build: