add setup step in CI

Author: chrisirhc

.github/workflows/ci.yml

@@ -23,6 +23,9 @@ jobs:
       run: |
         echo vendor/flutter/bin >> "$GITHUB_PATH"
 
+    - name: Run setup
+      run: tools/setup-vendor-flutter
+
     - name: Display version (Temporary)
       run: |
         flutter --version