deps: update actions/setup-go action to v6

Author: renovate-bot

.github/workflows/conformance.yaml

@@ -33,7 +33,7 @@ jobs:
       with:
         distribution: zulu
         java-version: 8
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
         go-version: '>=1.20.2'
     - run: java -version