The parser chokes on 1.5dppx

[nex3]

• Operating System (or Browser): RunKit
• Node Version: 10.18.0
• postcss-values-parser Version: 3.1.1

How Do We Reproduce?

https://runkit.com/nex3/5e446258c092240013ead2f1

const pvp = require('postcss-values-parser')
pvp.parse("1.5dppx")

Expected Behavior

I expect this to parse as a Numeric.

I chose to highlight dppx here because it's a specified unit, but this will reproduce with any unit string postcss-values-parser doesn't explicitly recognize. I would more broadly expect anything matching <dimension-token> to parse as a Numeric, even if its unit isn't specified yet. This is more future-proof as the specification evolves, and more friendly to postprocessors that may define their own custom units.

Actual Behavior

It throws a CssSyntaxError.

[shellscape]

Fixed in #109