fix actions

.github/workflows/build.yml

@@ -8,11 +8,11 @@ jobs:
 
     steps:
       - uses: actions/checkout@v3
-      - name: set up JDK 17
+      - name: set up JDK 21
         uses: actions/setup-java@v3
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
       - name: grant execute permission for gradlew
         run: chmod +x gradlew
       - name: build with gradle
@@ -21,4 +21,4 @@ jobs:
         uses: actions/upload-artifact@v3
         with:
           name: artifacts
-          path: build/libs/
+          path: build/libs/