Update build_test.yml

Author: AlexV525

.github/workflows/build_test.yml

@@ -41,4 +41,5 @@ jobs:
       - run: flutter --version
       - run: flutter pub get
       - run: flutter analyze lib example/lib
+      - run: sudo echo "y" | sudo $ANDROID_HOME/tools/bin/sdkmanager "ndk;20.0.5594570"
       - run: cd example; flutter build apk --debug