Fix analysis warnings

Author: mvanbeusekom

analysis_options.yaml

@@ -1,4 +1,4 @@
-include: package:pedantic/analysis_options.1.8.0.yaml
+include: package:pedantic/analysis_options.yaml
 analyzer:
   exclude:
     # Ignore generated files

lib/src/google_api_availability.dart

@@ -14,7 +14,7 @@ class GoogleApiAvailability {
   /// Acquires an instance of the [GoogleApiAvailability] class.
   static const GoogleApiAvailability instance = GoogleApiAvailability._();
 
-  static MethodChannel _methodChannel = const MethodChannel(
+  static final MethodChannel _methodChannel = const MethodChannel(
       'flutter.baseflow.com/google_api_availability/methods');
 
   /// This feature is only available on Android devices. On any other platforms
@@ -26,7 +26,7 @@ class GoogleApiAvailability {
       return GooglePlayServicesAvailability.notAvailableOnPlatform;
     }
 
-    final int? availability = await _methodChannel.invokeMethod(
+    final availability = await _methodChannel.invokeMethod(
         'checkPlayServicesAvailability',
         <String, bool>{'showDialog': showDialogIfNecessary});
 

lib/src/models/google_play_services_availability.dart

@@ -1,6 +1,9 @@
+/// Indicates possible states of the Google Api Services availability.
 class GooglePlayServicesAvailability {
   const GooglePlayServicesAvailability._(this.value);
 
+  /// Represents the integer value of the Google Api Services availability
+  /// state.
   final int value;
 
   /// Google Play services are installed on the device and ready to be used.
@@ -35,6 +38,7 @@ class GooglePlayServicesAvailability {
   static const GooglePlayServicesAvailability unknown =
       GooglePlayServicesAvailability._(7);
 
+  /// Returns a list with all possible Google Api Availability states.
   static const List<GooglePlayServicesAvailability> values =
       <GooglePlayServicesAvailability>[
     success,