Add support for onSave

[BirkAndMe]

It would be great to have an option, to run phpcs on save. So the phpcs.enable worked the same way as php.validate.run

[drmonkeyninja]

I was just about to raise an issue for the same request. I think this would be a really useful setting for people. It can be a little annoying seeing the code highlighted as breaking the standards when you're halfway through typing something out.

[drmonkeyninja]

It looks like there is already a merge request for this: https://github.com/ikappas/vscode-phpcs/pull/116.