Migrating to videojs-contrib-ads 4.0.0

Version 4 of videojs-contrib-ads is mainly about improving code quality. Functional changes are in support of that effort.

Migration

A playing event is no longer sent before a preroll ad. This is because a playing event should only be sent when content actually plays. If your integration relies on this event being fired at this time, consider another solution.
Contrib-ads expects your plugin to send a "playing" event when an ad starts playing, which will be redispatched as "adplaying". This may happen automatically, for example, if you play your ad in the content's video element.
The contentplayback event has been removed. Use playing instead.
videojs.ads.global.js and videojs.ads.global.min.js have been removed. Use videojs.ads.js or videojs.ads.min.js instead.
videojs.ads.css is now available in the dist folder rather than the src folder. Your integration should be updated to include it from there.