Feat: add GitHub Actions conf file

add buildapp.yml for build apk and create release with apk

Author: DmitriyLewen

.github/workflows/buildapp.yml

@@ -0,0 +1,29 @@
+name: buildapp
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  build:
+    name: Create Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set Up flutter
+        uses: subosito/flutter-action@v1
+
+      - name: Get flutter dependencies
+        run: flutter pub get
+
+      - name: Build apk
+        run: flutter build apk --release
+
+      - name: Create release and copy apk
+        uses: ncipollo/release-action@v1
+        with:
+          artifacts: "build/app/outputs/flutter-apk/*-release.apk"
+          token: ${{ secrets.GITHUB_TOKEN }}