Add amake/dart-flutter-compat to verify Flutter compatibility.

Author: renggli

.github/workflows/dart.yml

@@ -20,7 +20,7 @@ jobs:
         with:
           path: "~/.pub-cache/hosted"
           key: "os:ubuntu-latest;pub-cache-hosted;dart:stable"
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dart-lang/setup-dart@v1
       - name: "Dependencies"
         run: dart pub upgrade --no-precompile
@@ -38,3 +38,12 @@ jobs:
           dart pub global run coverage:test_with_coverage --test test/all_test.dart
       - name: "Upload coverage"
         uses: codecov/codecov-action@v3
+  check:
+    name: "Flutter CI"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: amake/dart-flutter-compat@v1
+        with:
+          channel: stable
+          cache: true