title: Could not build the application after change firebase_core from 0.4.4 to 0.5.2 on iOS Simulator
body: <p>I changed firebase core deoendecies from 0.4.4 to 0.5.2.
  But if i try to build my project, following error generates:</p>
  <pre><code>/Users/mrcube72/DEV/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_core-0.5.2/ios/Classes/FLTFirebasePlugin.h:9:9: error: include of non-modular header inside framework module 'firebase_core.FLTFirebasePlugin': '/Users/??????/DEV/Projects/futapp/ios/Pods/Headers/Public/FirebaseCore/FirebaseCore.h' [-Werror,-Wnon-modular-include-in-framework-module]
      #import &lt;FirebaseCore/FirebaseCore.h&gt;
              ^
      1 error generated.
      /Users/??????/DEV/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.18.3/ios/Classes/FLTFirebaseAuthPlugin.m:5:9: fatal error: could not build module 'firebase_core'
      #import &lt;firebase_core/FLTFirebasePluginRegistry.h&gt;
       ~~~~~~~^
      2 errors generated.
  </code></pre>
  <p>What is the problem? How can i resolve this problem?
  I tried reinstall pods, etc...
  Thank for the answers...</p>