Update release6.x.yml

Author: shuzijun

.github/workflows/release6.x.yml

@@ -25,10 +25,10 @@ jobs:
       if: ${{ github.event_name == 'workflow_dispatch'}}
       run: echo "LD_VERSION=${{ github.event.inputs.version }}" >> $GITHUB_ENV
 
-    - name: Set up JDK 11
+    - name: Set up JDK 1.8
       uses: actions/setup-java@v1
       with:
-        java-version: 11
+        java-version: 1.8
 
     - name: Grant execute permission for gradlew
       run: chmod +x gradlew