Add github workflows (#30)

.github/workflows/analysis.yml

@@ -0,0 +1,27 @@
+name: Analysis
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  analysis:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Fetch Flutter SDK
+        run: |
+          git clone --depth=1 https://github.com/flutter/flutter.git
+          cd flutter
+          git fetch --depth=1 https://github.com/flutter/flutter.git `cat ../bin/internal/flutter.version`
+          git checkout FETCH_HEAD
+
+      - name: Install pub dependencies
+        run: flutter/bin/flutter pub get
+
+      - name: Verify formatting
+        run: flutter/bin/dart format --output=none --set-exit-if-changed lib
+
+      - name: Analyze project source
+        run: flutter/bin/dart analyze --fatal-warnings lib