Add workflow

.github/workflows/pr.yaml

@@ -0,0 +1,22 @@
+on:
+  pull_request:
+    types: [opened, synchronize]
+    branches:
+      - main
+
+jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: "3.19.0"
+      - name: Get packages
+        run: flutter pub get
+      - name: Analyze
+        run: flutter analyze
+      - name: Test
+        run: flutter test