add Set up Flutter step

Author: nickf2k

.github/workflows/firebase-hosting-merge.yml

@@ -10,8 +10,11 @@ jobs:
   build_and_deploy:
     runs-on: ubuntu-latest
     steps:
-
       - uses: actions/checkout@v3
+      - name: Set up Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: '3.19.0'
       - run: flutter build web
       - uses: FirebaseExtended/action-hosting-deploy@v0
         with:

.github/workflows/firebase-hosting-pull-request.yml

@@ -8,12 +8,13 @@ jobs:
     if: '${{ github.event.pull_request.head.repo.full_name == github.repository }}'
     runs-on: ubuntu-latest
     steps:
-     - name: Set Up Flutter
+      - uses: actions/checkout@v3
+
+      - name: Set Up Flutter
         uses: subosito/flutter-action@v2
         with:
           flutter-version: '3.19.0'
           channel: 'stable'
-      - uses: actions/checkout@v3
       - run: flutter build web
       - uses: FirebaseExtended/action-hosting-deploy@v0
         with: