Update gradle/actions action to v6

Author: renovate[bot]

.github/workflows/publish.yml

@@ -89,7 +89,7 @@ jobs:
         with:
           distribution: "corretto"
           java-version: "17"
-      - uses: gradle/actions/setup-gradle@v5
+      - uses: gradle/actions/setup-gradle@v6
       - uses: actions/download-artifact@v8
         with:
           pattern: libvortex_jni_*.zip