v0.22.4 - Fixing Vue + Typescript bug & other minor things

Yes! A new release - but just some minor fixes.

To upgrade: yarn upgrade

Changes: v0.22.3..v0.22.4

Documentation: http://symfony.com/doc/current/frontend.html

Highlights:

• #483 Add new methods isDev() and isDevServer() - thanks to @Kocal
• #484 Allow to import .vue files when using TypeScript - thanks to @Lyrkan
• #485 Fix small mistakes in shared-entry-concat-plugin.js and validator.js - thanks to @Lyrkan