ci: 升级 Actions 版本，消除 Node.js 20 弃用警告

actions/checkout v4 -> v7, setup-java v4 -> v6,
upload-artifact v4 -> v7, setup-android v3 -> v4

Author: qpalzm2332933171-droid

.github/workflows/build.yml

@@ -12,17 +12,17 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up JDK
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v6
         with:
           distribution: temurin
           java-version: '21'
           cache: gradle
 
       - name: Set up Android SDK
-        uses: android-actions/setup-android@v3
+        uses: android-actions/setup-android@v4
 
       - name: Show toolchain versions
         run: |
@@ -34,7 +34,7 @@ jobs:
         run: ./gradlew :app:assembleDebug --no-daemon --console=plain
 
       - name: Upload APK
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: app-debug
           path: app/build/outputs/apk/debug/*.apk