Tweak Java version

Author: microbit-matt-hillsdon

.github/workflows/android-build.yml

@@ -29,7 +29,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: "temurin"
-          java-version: "17"
+          java-version: "21"
 
       - run: npm ci
         env: