title: flutter_downloader build exception
body: <p>I want to use flutter_downloader 1.1.6 in my project, flutter packages get is complete but I can't build an apk, it throws exception:</p>
  
  <pre><code>Launching lib\main.dart on ONEPLUS A5000 in debug mode...
  Initializing gradle...
  Resolving dependencies...
  Gradle task 'assembleDebug'...
  
  Finished with error: FormatException: Bad UTF-8 encoding 0xb4 (at offset 166)
  </code></pre>
  
  <p>Here is my dependencies:</p>
  
  <pre><code>dependencies:
    flutter:
      sdk: flutter
  
    dio: ^1.0.13
  
    crypto: ^2.0.6
  
    fluttertoast: ^2.2.6
  
    sqflite: ^1.0.0
    path_provider: ^0.5.0+1
    shared_preferences: ^0.4.2
  
    url_launcher: ^4.0.0
  
    zefyr: ^0.3.1
  
    cached_network_image: ^0.6.0+1
    image_picker: ^0.4.5
  
    flutter_downloader: ^1.1.6
  </code></pre>
  
  <p>I have tried some solutions on the Internet but they don't work.
  I want to know how to fix the problem and why it occurs.</p>