Add GitHub Action for Flutter Web deployment

.github/workflows/deploy.yml

@@ -0,0 +1,31 @@
+name: Build and Deploy Flutter Web
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v4
+
+      - name: Set up Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: "stable"
+
+      - name: Flutter Pub Get
+        run: flutter pub get
+
+      - name: Build Flutter Web
+        run: flutter build web
+
+      - name: Deploy to GitHub Pages
+        uses: actions/deploy-pages@v4
+        with:
+          branch: "gh-pages"
+          folder: "build/web"