Set showModal configuration default FadeScaleTransitionConfiguration

Author: mono0926

packages/animations/example/lib/fade_scale_transition.dart

@@ -85,7 +85,6 @@ class _FadeScaleTransitionDemoState extends State<FadeScaleTransitionDemo>
                   onPressed: () {
                     showModal<void>(
                       context: context,
-                      configuration: const FadeScaleTransitionConfiguration(),
                       builder: (BuildContext context) {
                         return _ExampleAlertDialog();
                       },

packages/animations/lib/src/modal.dart

@@ -4,6 +4,8 @@
 
 import 'package:flutter/material.dart';
 
+import 'fade_scale_transition.dart';
+
 /// Signature for a function that creates a widget that builds a
 /// transition.
 ///
@@ -45,7 +47,7 @@ typedef _ModalTransitionBuilder = Widget Function(
 /// the modal's characteristics.
 Future<T> showModal<T>({
   @required BuildContext context,
-  @required ModalConfiguration configuration,
+  ModalConfiguration configuration = const FadeScaleTransitionConfiguration(),
   bool useRootNavigator = true,
   WidgetBuilder builder,
 }) {