title: 'UserAgent.h' file not found flutter firebase iOS
body: <p>I am working on flutter application with firebase, when i use the firebaseAuth plugin application give the following error</p>
  
  <pre><code>Launching lib/main.dart on iPhone 11 Pro Max in debug mode...
  Running pod install...
  Running Xcode build...
  Xcode build done.                                           131.2s
  Failed to build iOS app
  Error output from Xcode build:
  ↳
  2020-02-28 16:05:06.832 XCBBuildService[68423:382033] Failed to remove: 
  /Users/apple/Library/Developer/Xcode/DerivedData/Runner- hfqwisipukhnqobtbsvjhfltdbgs/Build/Intermediates.noindex/XCBuildData/1be627f6c729f1a388e5fec96804d392-manifest.xcbuild: unlink(/Users/apple/Library/Developer/Xcode/DerivedData/Runner-hfqwisipukhnqobtbsvjhfltdbgs/Build/Intermediates.noindex/XCBuildData/1be627f6c729f1a388e5fec96804d392-manifest.xcbuild): No such file or directory (2)
  2020-02-28 16:05:07.269 XCBBuildService[68423:382033] Failed to remove: /Users/apple/Library/Developer/Xcode/DerivedData/Runner-hfqwisipukhnqobtbsvjhfltdbgs/Build/Intermediates.noindex/XCBuildData/1be627f6c729f1a388e5fec96804d392-desc.xcbuild: unlink(/Users/apple/Library/Developer/Xcode/DerivedData/Runner-hfqwisipukhnqobtbsvjhfltdbgs/Build/Intermediates.noindex/XCBuildData/1be627f6c729f1a388e5fec96804d392-desc.xcbuild): No such file or directory (2)
  * BUILD FAILED *
  
  
  Xcode's output:
  ↳
  /Users/apple/Library/Android/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.15.5+2/darwin/Classes/FLTFirebaseAuthPlugin.m:7:9: fatal error: 'UserAgent.h' file not found
  #import "UserAgent.h"
          ^~~~~~~~~~~~~
  1 error generated.
  note: Using new build system
  note: Planning build
  note: Constructing build description
  
  Could not build the application for the simulator.
  Error launching application on iPhone 11 Pro Max.
  </code></pre>
  
  <p>i am using these libraries-</p>
  
  <pre><code>firebase_auth: ^0.15.5+2
  firebase_storage: ^3.1.1
  cloud_firestore: ^0.13.4
  </code></pre>
  
  <p>anyone have idea how to solve this error?, i have already done following things</p>
  
  <pre><code>flutter clean
  deleted podfile.lock
  deleted pods folder
  pod deintegrate
  pod repo update
  pod install
  </code></pre>
  
  <p>but don't help me to solve this error</p>