Fix Dart 2 type error in local_auth (#395)

diff --git a/packages/local_auth/CHANGELOG.md b/packages/local_auth/CHANGELOG.md
index c4eaafe..add32fb 100644
--- a/packages/local_auth/CHANGELOG.md
+++ b/packages/local_auth/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.1.2
+
+* Fixed Dart 2 type error.
+
 ## 0.1.1
 
 * Simplified and upgraded Android project template to Android SDK 27.
diff --git a/packages/local_auth/android/build.gradle b/packages/local_auth/android/build.gradle
index a19fb90..d545210 100644
--- a/packages/local_auth/android/build.gradle
+++ b/packages/local_auth/android/build.gradle
@@ -34,5 +34,5 @@
 }
 
 dependencies {
-    compile "com.android.support:support-v4:26.1.0"
+    implementation "com.android.support:support-v4:26.1.0"
 }
diff --git a/packages/local_auth/lib/local_auth.dart b/packages/local_auth/lib/local_auth.dart
index ab5d923..c5160d1 100644
--- a/packages/local_auth/lib/local_auth.dart
+++ b/packages/local_auth/lib/local_auth.dart
@@ -53,7 +53,7 @@
     bool stickyAuth: false,
     AndroidAuthMessages androidAuthStrings: const AndroidAuthMessages(),
     IOSAuthMessages iOSAuthStrings: const IOSAuthMessages(),
-  }) {
+  }) async {
     assert(localizedReason != null);
     final Map<String, Object> args = <String, Object>{
       'localizedReason': localizedReason,
@@ -71,6 +71,6 @@
               'operating systems.',
           details: 'Your operating system is ${Platform.operatingSystem}');
     }
-    return _channel.invokeMethod('authenticateWithBiometrics', args);
+    return await _channel.invokeMethod('authenticateWithBiometrics', args);
   }
 }
diff --git a/packages/local_auth/pubspec.yaml b/packages/local_auth/pubspec.yaml
index 777d675..9e2f927 100644
--- a/packages/local_auth/pubspec.yaml
+++ b/packages/local_auth/pubspec.yaml
@@ -1,7 +1,7 @@
 name: local_auth
 description: Flutter plugin for Android and iOS device authentication sensors
   such as Fingerprint Reader and Touch ID.
-version: 0.1.1
+version: 0.1.2
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/local_auth