title: 'flutter pub get' does not work in VSCode
body: <p>I'm currently developing flutter application with VSCode and want to add some packages. ex) dropdown_menu</p>
  <p>I did <strong>flutter pub get / flutter packages get / clicking down arrow button in vscode(get Packages)</strong>
  and this is all I get everytime</p>
  <pre><code>PS D:\VSCodeProjects\testt&gt; flutter pub get
  Running &quot;flutter pub get&quot; in testt...                               0.4s
  PS D:\VSCodeProjects\testt&gt; 
  </code></pre>
  <p>this is my code in pubspec.</p>
  <pre><code>dependencies:
    flutter:
      sdk: flutter
    cupertino_icons: ^0.1.3
    dropdown_menu: ^1.1.0
  </code></pre>
  <p>I did turn on / off program( and computer)  , restart,</p>
  <p>and</p>
  <p>flutter clean</p>
  <p>flutter packages get</p>
  <p>flutter packages upgrade</p>
  <p>Does anybody know how to solve??</p>