dart.yml: rename art to flutter

Author: Sergey Khomushin

.github/workflows/dart.yml

@@ -25,18 +25,18 @@ jobs:
       - uses: dart-lang/setup-dart@9a04e6d73cca37bd455e0608d7e5092f881fd603
 
       - name: Install dependencies
-        run: dart pub get
+        run: flutter pub get
 
       # Uncomment this step to verify the use of 'dart format' on each commit.
       # - name: Verify formatting
       #   run: dart format --output=none --set-exit-if-changed .
 
       # Consider passing '--fatal-infos' for slightly stricter analysis.
       - name: Analyze project source
-        run: dart analyze
+        run: flutter analyze
 
       # Your project will need to have tests in test/ and a dependency on
       # package:test for this step to succeed. Note that Flutter projects will
       # want to change this to 'flutter test'.
       - name: Run tests
-        run: dart test
+        run: flutter test