fails to run on ios - MethodNotImplemented

I am using this plugin and trying to run my app on iOS simulator. However when I try to run this from xcode I am getting this error.
```
Undefined symbols for architecture i386:
"_FlutterMethodNotImplemented", referenced from:
-[FlutterWebviewPlugin handleMethodCall:result:] in FlutterWebviewPlugin.o
"_OBJC_CLASS_$_FlutterMethodChannel", referenced from:
objc-class-ref in FlutterWebviewPlugin.o
ld: symbol(s) not found for architecture i386
```

Plugin version - ` flutter_webview_plugin: ^0.3.0+2`

Please help me fix this. Thanks for making this awesome library.

output of flutter doctor

```
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v0.11.9, on Mac OS X 10.14.1 18B75, locale en-IN)
[✓] Android toolchain - develop for Android devices (Android SDK 28.0.3)
[✓] iOS toolchain - develop for iOS devices (Xcode 10.1)
[✓] Android Studio (version 3.2)
[✓] Connected device (1 available)

• No issues found!

```

首先，使用 flutter_webview_plugin 版本 0.3.0+2 重现 iOS 模拟器构建，并检查针对 FlutterMethodNotImplemented 和 FlutterMethodChannel 报告的链接器错误。当插件能够在 iOS 模拟器上链接并运行，且不再出现这些未定义符号错误时，即表示完成。

由索引模型根据 Issue 内容生成。