Update stylelint to version 6.7.1 🚀

[greenkeeperio-bot]

Hello lovely humans,

stylelint just published its new version 6.7.1.

State	Update 🚀
Dependency	stylelint
New version	6.7.1
Type	devDependency

This version 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 stylelint.
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.

Do you have any ideas how I could improve these pull requests? Did I report anything you think isn’t right?
Are you unsure about how things are supposed to work?

There is a collection of frequently asked questions and while I’m just a bot, there is a group of people who are happy to teach me new things. Let them know.

Good luck with your project ✨

You rock!

🌴

---

The new version differs by 20 commits .

• 784e4c2 Prepare 6.7.1
• d937d72 Prepare changelog
• a5244c7 Fix no-descending-specificity rule to ensure comparing of numbers not strings (#1518)
• d3ee404 Merge pull request #1514 from stylelint/selector-type-fixes
• 039349d Add selector-type fixes to changelog
• d40582b Ignore non-standard keyframe selector usage
• b96b7a3 Ignore factional keyframe selectors
• bc43507 Merge pull request #1510 from stylelint/postcss-api-docs
• 871d832 Merge pull request #1512 from stylelint/block-before-crlf
• f23ec6f Fix CRLF warning positioning
• 0ad0c43 Use PostCSS JS API within PostCSS plugin doc examples
• 981759d Correct build plugin links and order
• 78c8b43 Add Broccoli and Ember-cli plugins (#1403)
• ae41029 Merge pull request #1507 from stylelint/standardise-readmes
• e858d62 Fix md lint warning

There are 20 commits in total. See the full diff.

---

This pull request was created by greenkeeper.io.

_{Tired of seeing this sponsor message? ⚡ greenkeeper upgrade}