ci: set jdk to 21

Author: joe-p

.github/workflows/android_ci.yml

@@ -16,6 +16,12 @@ jobs:
       - name: Checkout Code
         uses: actions/checkout@v5
 
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: 1.85.0