message: Align setupWebserver signature for SlackController type
diff: @@ -279,7 +279,7 @@ declare namespace botkit {
  createHomepageEndpoint(webserver: any): this;
  createOauthEndpoints(webserver: any, callback: (err: Error, req: any, res: any) => void): this;
  createWebhookEndpoints(webserver: any, authenticationTokens?: string[]): this;
  - setupWebserver();
  + setupWebserver(port: number | string, cb: (err: Error, webserver: any) => void): this;
  getAuthorizeURL(team_id: string, redirect_params: any): string;
  }
  interface SlackMessage extends Message {
  