chore(ci): 升级JDK版本至21

- 将GitHub Actions中的JDK设置从版本11更新为版本21
- 使用actions/setup-java@v4动作来配置Java环境
- 保持Android SDK设置步骤不变
- 确保CI构建流程使用最新的Java版本

Signed-off-by: Jesse205 <2055675594@qq.com>

Author: Jesse205

.github/workflows/build.yml

@@ -18,11 +18,11 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Set up JDK 11
+      - name: Set up JDK
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: '11'
+          java-version: '21'
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3