migrate from cfx to jpm

[smlng]

mail from `amo-editors@mozilla.org:

A reviewer requested further information from you regarding version 2.2 of your add-on RPKI Validator.

erosman wrote:

Add-ons built with "cfx" are no longer accepted.

Due to breaking changes in Firefox 44, add-ons packed with the "cfx" tool won't work any longer. To make your add-on compatible again, please use the "jpm" tool (http://mzl.la/1PwF5fY). You can find steps to migrate from "cfx" to "jpm" at http://mzl.la/1ncmH3A