reuse openjdk:17-jdk to trying avoid connection timeout

.gitea/workflows/ci.yaml

@@ -12,15 +12,12 @@ jobs:
   build:
     runs-on: ubuntu-latest
 
+    container:
+      image: dockerp.com/openjdk:17-jdk
+
     steps:
       - name: Checkout code
-        uses:  http://fly6516.synology.me:4000/Gitea_Action/checkout@v2
-
-      - name: Set up JDK 17
-        uses: http://fly6516.synology.me:4000/Gitea_Action/setup-java@v2
-        with:
-          java-version: '17'
-          distribution: 'temurin'
+        uses: http://fly6516.synology.me:4000/Gitea_Action/checkout@v2
 
       - name: Compile Java program
         run: javac HelloWorld.java -d ./build/classes