add app build

Author: detherminal

.github/workflows/build-apk.yml

@@ -44,4 +44,7 @@ jobs:
       - name: Build lib
         run: |
           cd $(pwd)/../xmrwallet/external-libs
-          make
+          make
+
+      - name: Build Android App
+        uses: sparkfabrik/[email protected]