add build workflow

.github/workflows/build.yml

@@ -0,0 +1,40 @@
+name: Build debug APK
+
+on:
+  push:
+    branches:
+      - '*'
+    paths-ignore:
+      - '**.md'
+      - '.idea/*'
+      - 'LICENSE'
+  pull_request:
+    branches:
+      - '*'
+    paths-ignore:
+      - '**.md'
+      - '.idea/*'
+      - 'LICENSE'
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: set up JDK 17
+        uses: actions/setup-java@v2
+        with:
+          java-version: 17
+          distribution: 'temurin'
+          cache: 'gradle'
+
+      - name: Build APK
+        run: chmod +x ./gradlew && ./gradlew assembleDebug
+
+      - name: Upload APK
+        uses: actions/upload-artifact@v2
+        with:
+          name: QWeather
+          path: app/build/outputs/apk/debug/app-debug.apk