def update(plugins, specific, **opts)
      specific ||= []
      update = opts.merge({gems: specific.empty? ? true : specific})
      internal_install(plugins, update)
    end
def update(plugins, specific, **opts)
      specific ||= []
      update = opts.merge({gems: specific.empty? ? true : specific})
      internal_install(plugins, update)
    end
Update updates the given plugins, or every plugin if none is given.

 @param [Hash] plugins
 @param [Array<String>] specific Specific plugin names to update. If
   empty or nil, all plugins will be updated.