Update actions/setup-go action to v6

Author: renovate[bot]

.github/workflows/go.yml

@@ -17,7 +17,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Set up Go
-      uses: actions/setup-go@v4
+      uses: actions/setup-go@v6
       with:
         go-version: '1.25.x'