Aperture: Add GitHub actions build workflow

Change-Id: I13b49a7690184250223d48ec9742446939ca8e83
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..3d2401d
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,24 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repo
+      uses: actions/checkout@v1
+
+    - name: Setup JDK 11
+      uses: actions/setup-java@v1
+      with:
+        java-version: 11
+
+    - name: Build with Gradle
+      run: ./gradlew assembleDebug
+
+    - uses: actions/upload-artifact@v3
+      with:
+        name: app-debug.apk
+        path: app/build/outputs/apk/debug/app-debug.apk