Update actions/setup-go from v5 to v6

Author: leighmcculloch

.github/actions/setup-go/action.yml

@@ -4,7 +4,7 @@ runs:
   using: "composite"
   steps:
     - name: Set up Go
-      uses: actions/setup-go@v5
+      uses: actions/setup-go@v6
       with:
         go-version: '1.24'
         # unfortunately we cannot use the provided caching because it uses the