Added recommended extensions

Author: JHubi1

.github/workflows/build.yaml

@@ -1,4 +1,4 @@
-name: Build Script
+name: Build app
 on:
   workflow_dispatch:
     inputs:

.vscode/extensions.json

@@ -0,0 +1,7 @@
+{
+    "recommendations": [
+        "dart-code.dart-code",
+        "dart-code.flutter",
+        "github.vscode-github-actions"
+    ]
+}