Update postcss-discard-comments to the latest version 🚀

[greenkeeper[bot]]

Version 4.0.0-rc.2 of postcss-discard-comments just got published.

Dependency	postcss-discard-comments
Current Version	2.0.4
Type	devDependency

The version 4.0.0-rc.2 is not covered by your current version range.

Without accepting this pull request your project will work just like it did before. There might be a bunch of new features, fixes and perf improvements that the maintainers worked on for you though.

I recommend you look into these changes and try to get onto the latest version of postcss-discard-comments. Given that you have a decent test suite, a passing build is a strong indicator that you can take advantage of these changes by merging the proposed change into your project. Otherwise this branch is a great starting point for you to work on the update.

---

Not sure how things should work exactly?

There is a collection of [frequently asked questions](https://greenkeeper.io/faq.html) and of course you may always [ask my humans](https://github.com/greenkeeperio/greenkeeper/issues/new).

---

Your Greenkeeper Bot :palm_tree:

[greenkeeper[bot]]

Version 4.0.0 just got published.

Update to this version instead 🚀

[greenkeeper[bot]]

• The devDependency postcss-discard-comments was updated from 2.0.4 to 4.0.1.

Update to this version instead 🚀

Release Notes for 4.0.1

Bug Fixes

• browserslist version incompatibility with caniuse-api

[greenkeeper[bot]]

• The devDependency postcss-discard-comments was updated from 2.0.4 to 4.0.2.

Update to this version instead 🚀

Release Notes for 4.0.2

Bug Fixes

• postcss-merge-longhand don't explode declarations with custom properties.
• postcss-colormin now better transform to hsl.