.github: Add workflow for building the APK

Signed-off-by: Sushrut1101 <guptasushrut@gmail.com>

.github/workflows/build.yml

@@ -0,0 +1,32 @@
+name: Build the APK
+
+env:
+  APKTOOL_VER: 2.7.0
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+
+    - uses: actions/setup-java@v3
+      with:
+        distribution: 'adopt-hotspot'
+        java-version: '8'
+
+    - uses: robinraju/release-downloader@v1.5
+      with:
+        repository: 'iBotPeaches/Apktool'
+        tag: 'v${{ env.APKTOOL_VER }}'
+        fileName: 'apktool_${{ env.APKTOOL_VER }}.jar'
+
+    - run: java -jar apktool_${{ env.APKTOOL_VER }}.jar b .
+
+    - uses: actions/upload-artifact@v3
+      with:
+        name: APK
+        path: dist/ImsService.apk