Add Github Actions .yml

.github/workflows/dart.yml

@@ -0,0 +1,25 @@
+name: dart
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - uses: actions/setup-java@v1
+      with:
+        java-version: '12.x'
+    - uses: subosito/flutter-action@v1
+      with:
+        channel: 'stable'
+    - name: Version
+      run: flutter doctor -v
+    - name: Install dependencies
+      run: flutter pub get
+    - name: Format
+      run: dartfmt -n --set-exit-if-changed .
+    - name: Linter
+      run: dartanalyzer . --fatal-hints