updates rest-client to address vulnerability   * [vulnerability](https://isitvulnerable.com/vulns/557513c4-f150-429c-b7f2-58e21936a535)
updates rest-client to address vulnerability
  * [vulnerability](https://isitvulnerable.com/vulns/557513c4-f150-429c-b7f2-58e21936a535)

jeremytregunna/ruby-trello,danmcp/ruby-trello,CodingZeal/ruby-trello,ksamc/ruby-trello,brycemcd/ruby-trello,dotmartyr/ruby-trello,gorenje/ruby-trello,rossta/ruby-trello,playtestcloud/ruby-trello,jayshreeanand/ruby-trello,joneslee85/ruby-trello