update async_tools and flutter bindings

veilid-flutter/packages/veilid_test/lib/src/veilid_fixture.dart

@@ -163,10 +163,8 @@ class DefaultVeilidFixture implements VeilidFixture {
   Future<void> tearDown() async {
     assert(_fixtureMutex.isLocked, 'should not tearDown without setUp');
 
-    final cancelFut = _veilidUpdateSubscription?.cancel();
     await Veilid.instance.shutdownVeilidCore();
-    await cancelFut;
-
+    await _veilidUpdateSubscription?.cancel();
     await _updateStreamController.close();
 
     _veilidUpdateSubscription = null;

veilid-flutter/packages/veilid_test/pubspec.yaml

@@ -9,7 +9,7 @@ environment:
 
 # Add regular dependencies here.
 dependencies:
-  async_tools: ^0.1.1
+  async_tools: ^0.1.3
   veilid:
     path: ../..