No flexbox support

[erbridge]

Flexbox is now supported by parser-lib: CSSLint/parser-lib@7734add

[kozmoz]

Updating parser-lib should fix this. The flex box CSS properties are in parser-lib for about 4 months now ( CSSLint/parser-lib#91 ) and are part of parser-lib v0.2.4.

So fixing #448 "bump parserlib to v0.2.4" will also fix this one.

[nschonni]

As a temporary workaround you can uninstall and reinstall to get the latest parser-lib dependency

[cvrebert]

Fixed by #427?