title: No type or protocol named 'FlutterPluginRegistrar'
body: <p>Flutter issues on ios
  In XCode, Some library (SharedPreferences, Apple Sign-In) is showing errors:</p>
  <p><code>No type or protocol named 'FlutterPluginRegistrar'</code></p>
  <p>I already tried with: flutter clean, pod update, I cleaned pub-cache and reinstalled all the libraries, the only thing I did not do is delete the pod folder of the ios project (I did it once and then I could not recover the project)</p>
  <p><img src="https://i.stack.imgur.com/jVlBE.jpg" alt="screenshot" /></p>
  <pre><code>
  ** BUILD FAILED **
  
  
  Xcode's output:
  ↳
    Command CompileSwift failed with a nonzero exit code
    Command CompileSwift failed with a nonzero exit code
    In file included from
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:5
    :
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.h:7
    :51: error: no type or protocol named 'FlutterPlugin'
    @interface FLTSharedPreferencesPlugin : NSObject &lt;FlutterPlugin&gt;
                                                      ^
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:1
    1:41: error: no type or protocol named 'FlutterPluginRegistrar'
    + (void)registerWithRegistrar:(NSObject&lt;FlutterPluginRegistrar&gt; *)registrar {
                                            ^
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:1
    2:3: error: use of undeclared identifier 'FlutterMethodChannel'
      FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:CHANNEL_NAME
      ^
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:1
    2:25: error: use of undeclared identifier 'channel'
      FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:CHANNEL_NAME
                            ^
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:1
    2:36: error: use of undeclared identifier 'FlutterMethodChannel'
      FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:CHANNEL_NAME
                                       ^
    /Users/zippyttech/flutter/.pub-cache/hosted/pub.dartlang.org/shared_preferences-0.5.10/ios/Classes/FLTSharedPreferencesPlugin.m:1
    4:4: error: use of undeclared identifier 'channel'
      [channel setMethodCallHandler:^(FlutterMethodCall *call, FlutterResult result) {
       ^
    6 errors generated.
    note: Using new build system
    note: Building targets in parallel
    note: Planning build
    note: Constructing build description
  
  Encountered error while building for device.```
  
  Flutter Version: Flutter 1.20.3 • channel stable • https://github.com/flutter/flutter.git
  Framework • revision 216dee60c0 (10 days ago) • 2020-09-01 12:24:47 -0700
  Engine • revision d1bc06f032
  Tools • Dart 2.9.2
  
  apple_sign_in: ^0.1.0
  
  shared_preferences: ^0.5.10
  </code></pre>