[Windows] Fix set maximizable throwing an error

[jcbinet]

An error is thrown when we call setMaximizable because we are using invokeListMethod, instead of invokeMethod.

• Replace invokeListMethod with invokeMethod
• Modify method to be asynchronous

Fixes #219

[damywise]

My bad, I made a typo with autocomplete a few months ago when implementing setMaximizable.

[MahmoudKEA]

@jcbinet Please edit your commit to be asynchronous like this

Future<void> setMaximizable(bool isMaximizable) async {
    final Map<String, dynamic> arguments = {
      'isMaximizable': isMaximizable,
    };
    await _channel.invokeMethod('setMaximizable', arguments);
 }

[jcbinet]

@MahmoudKhalid Good catch! It's updated

[MahmoudKEA]

@MahmoudKhalid Good catch! It's updated

Good job, Thank you