title: Updating composer throws exception Class Fxp\Composer\AssetPlugin\Repository\NpmRepository does not exist
body: <p>I recently ran latest composer installation for a Yii2 basic application template.</p>
  
  <p>But running <code>php composer.phar install</code> throws this exception:</p>
  
  <blockquote>
    <p>Class Fxp\Composer\AssetPlugin\Repository\NpmRepository does not
    exist</p>
    
    <p>The "yiisoft/yii2-composer" plugin requires composer-plugin-api 1.0.0,
    this <em>WIL L</em> break in the future and it should be fixed ASAP (require
    ^1.0 for example).</p>
    
    <p>[ReflectionException]   Class
    Fxp\Composer\AssetPlugin\Repository\NpmRepository does not exist</p>
    
    <p>[ErrorException]</p>
    
    <p>Declaration of
    Fxp\Composer\AssetPlugin\Repository\AbstractAssetsRepository::w
    hatProvides() should be compatible with
    Composer\Repository\ComposerRepository::
    whatProvides(Composer\DependencyResolver\Pool $pool, $name,
    $bypassFilters = fal se)</p>
  </blockquote>
  
  <p>Here is my composer.json: </p>
  
  <pre><code>{
      "name": "yiisoft/yii2-app-basic",
      "description": "Yii 2 Basic Project Template",
      "keywords": ["yii2", "framework", "basic", "project template"],
      "homepage": "http://www.yiiframework.com/",
      "type": "project",
      "license": "BSD-3-Clause",
      "support": {
          "issues": "https://github.com/yiisoft/yii2/issues?state=open",
          "forum": "http://www.yiiframework.com/forum/",
          "wiki": "http://www.yiiframework.com/wiki/",
          "irc": "irc://irc.freenode.net/yii",
          "source": "https://github.com/yiisoft/yii2"
      },
      "minimum-stability": "stable",
      "require": {
          "php": "&gt;=5.4.0",
          "yiisoft/yii2": "&gt;=2.0.5",
          "yiisoft/yii2-bootstrap": "*",
          "yiisoft/yii2-swiftmailer": "*"
  
      },
      "require-dev": {
          "yiisoft/yii2-codeception": "*",
          "yiisoft/yii2-debug": "*",
          "yiisoft/yii2-gii": "*",
          "yiisoft/yii2-faker": "*"
      },
      "config": {
          "process-timeout": 1800
      },
      "scripts": {
          "post-create-project-cmd": [
              "yii\\composer\\Installer::postCreateProject"
          ]
      },
      "extra": {
          "yii\\composer\\Installer::postCreateProject": {
              "setPermission": [
                  {
                      "runtime": "0777",
                      "web/assets": "0777",
                      "yii": "0755"
                  }
              ],
              "generateCookieValidationKey": [
                  "config/web.php"
              ]
          },
          "asset-installer-paths": {
              "npm-asset-library": "vendor/npm",
              "bower-asset-library": "vendor/bower"
          }
      }
  }
  </code></pre>
  
  <p>What could have gone wrong? Anyone experiencing this?</p>