Update cssnano to the latest version 🚀

[greenkeeper]

Version 4.0.0 of cssnano was just published.

Dependency	cssnano
Current Version	3.10.0
Type	dependency

The version 4.0.0 is not covered by your current version range.

If you don’t accept this pull request, your project will work just like it did before. However, you might be missing out on a bunch of new features, fixes and/or performance improvements from the dependency update.

It might be worth looking into these changes and trying to get this project onto the latest version of cssnano.

If you have a solid test suite and good coverage, a passing build is a strong indicator that you can take advantage of these changes directly by merging the proposed change into your project. If the build fails or you don’t have such unconditional trust in your tests, this branch is a great starting point for you to work on the update.

---

Release Notes

4.0.0

Breaking changes

• We dropped support for Node 4, now requiring at least Node 6.9.

Features

• postcss-merge-longhand now optimises border-spacing property.

Bug Fixes

• postcss-normalize-unicode doesn't change U to lowercase for IE <= 11 and Edge <= 15.
• postcss-merge-longhand works with custom properties (Example a { border-style:dotted; border-style:var(--variable) }) correctly.
• postcss-ordered-values handle border property with invalid border width value correctly.
• postcss-merge-rules handles :-ms-input-placeholder and ::-ms-input-placeholder selectors correctly.
• postcss-merge-rules works with all property correctly.
• postcss-normalize-url don't handle empty url function.
• postcss-normalize-url handles data and *-extension:// URLs correctly.
• postcss-colormin adds whitespace after minified value and before function.
• postcss-minify-font-values better escapes font name.
• postcss-minify-params doesn't remove all for IE.

FAQ and help

There is a collection of frequently asked questions. If those don’t help, you can always ask the humans behind Greenkeeper.

---

Your Greenkeeper bot 🌴