code: function hasPlugin(deps, pluginName, version) {
      return !!deps.find(function(dep) {
          return dep.getName() === pluginName && (!version || dep.getVersion() === version);
      });
  }
docs: Test if a plugin is listed
  @param { {List<PluginDependency}} deps
  @param {String} plugin
  @param {String} version
  @return {Boolean}