[espresso] Update SDK requirement for null-safety

This plugin doesn't have any Dart code, but changing the SDK requirement
will prevent potential user confusion from it not showing up as
null-safe on Pub.

packages/espresso/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.1.0
+
+* Update SDK requirement for null-safety compatibility.
+
 ## 0.0.1+9
 
 * Update Flutter SDK constraint.

packages/espresso/example/lib/main.dart

@@ -27,7 +27,7 @@ class MyApp extends StatelessWidget {
 }
 
 class _MyHomePage extends StatefulWidget {
-  _MyHomePage({Key key, this.title}) : super(key: key);
+  _MyHomePage({Key? key, required this.title}) : super(key: key);
 
   // This widget is the home page of your application. It is stateful, meaning
   // that it has a State object (defined below) that contains fields that affect

packages/espresso/example/pubspec.yaml

@@ -3,22 +3,19 @@ description: Demonstrates how to use the espresso plugin.
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.12.0-259.9.beta <3.0.0"
+  flutter: ">=1.20.0"
 
 dependencies:
   flutter:
     sdk: flutter
 
-  # The following adds the Cupertino Icons font to your application.
-  # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^0.1.2
-
 dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_driver:
     sdk: flutter
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0
 
   espresso:
     # When depending on this package from a real application you should use:
@@ -28,44 +25,5 @@ dev_dependencies:
     # the parent directory to use the current plugin's version.
     path: ../
 
-# For information on the generic Dart part of this file, see the
-# following page: https://dart.dev/tools/pub/pubspec
-
-# The following section is specific to Flutter.
 flutter:
-
-  # The following line ensures that the Material Icons font is
-  # included with your application, so that you can use the icons in
-  # the material Icons class.
   uses-material-design: true
-
-  # To add assets to your application, add an assets section, like this:
-  # assets:
-  #  - images/a_dot_burr.jpeg
-  #  - images/a_dot_ham.jpeg
-
-  # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
-
-  # For details regarding adding assets from package dependencies, see
-  # https://flutter.dev/assets-and-images/#from-packages
-
-  # To add custom fonts to your application, add a fonts section here,
-  # in this "flutter" section. Each entry in this list should have a
-  # "family" key with the font family name, and a "fonts" key with a
-  # list giving the asset and other descriptors for the font. For
-  # example:
-  # fonts:
-  #   - family: Schyler
-  #     fonts:
-  #       - asset: fonts/Schyler-Regular.ttf
-  #       - asset: fonts/Schyler-Italic.ttf
-  #         style: italic
-  #   - family: Trajan Pro
-  #     fonts:
-  #       - asset: fonts/TrajanPro.ttf
-  #       - asset: fonts/TrajanPro_Bold.ttf
-  #         weight: 700
-  #
-  # For details regarding fonts from package dependencies,
-  # see https://flutter.dev/custom-fonts/#from-packages

packages/espresso/pubspec.yaml

@@ -1,11 +1,11 @@
 name: espresso
 description: Java classes for testing Flutter apps using Espresso.
-version: 0.0.1+9
+version: 0.1.0
 homepage: https://github.com/flutter/plugins/espresso
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
-  flutter: ">=1.10.0"
+  sdk: ">=2.12.0-259.9.beta <3.0.0"
+  flutter: ">=1.20.0"
 
 dependencies:
   flutter:
@@ -14,7 +14,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0
 
 # The following section is specific to Flutter.
 flutter: