title: Dart can't find git dependency but `flutter pub get` downloaded it
body: <p>I've created a plugin that I'm testing against a secondary flutter app. this purpose is to understand / validate my plugin is available to the integrating app, it's clearly not.</p>
  <p>I've included the dependency as follows:</p>
  <pre><code>dependencies:
    flutter:
     sdk: flutter
   concierge:
      git: git@github.com:flybits/flutter-concierge-plugin.git
  </code></pre>
  <p>After running <code>flutter pub get</code> I see the .flutter-depenedency file contains the plugin and a file path to the plugin.</p>
  <pre><code>concierge=/usr/local/Caskroom/flutter/2.5.3/flutter/.pub-cache/git/flutter-concierge-plugin-bf25c6bd87bd88f3c012ef06acd886bd6f2e68ec/
  firebase_auth=/usr/local/Caskroom/flutter/2.5.3/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-3.3.20/
  </code></pre>
  <p>And so on.</p>
  <p>checked on disk and found the directory. I'm confident the command worked. My issue is when I go to use it the demo app cannot find this plugin.</p>
  <pre><code>import 'package:concierge/concierge.dart';
  </code></pre>
  <p>but its able to find <code>firebase_auth</code></p>
  <p>The only different I can tell are the directories are different, one with /git/ the other with /hosting/</p>
  <p><em>I've installed flutter using HomeBrew</em></p>
  <p>Any help would be awesome.</p>
  <p>Thanks,
  Mike.</p>