Update dependency autoprefixer to v10

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
autoprefixer	devDependencies	major	9.8.6 -> 10.0.0

---

Release Notes

postcss/autoprefixer

### [`v10.0.0`](https://togithub.com/postcss/autoprefixer/releases/10.0.0) [Compare Source](https://togithub.com/postcss/autoprefixer/compare/9.8.6...10.0.0) Autoprefixer 10 is based on top of [PostCSS 8](https://togithub.com/postcss/postcss/releases/tag/8.0.0) (check **Known Issues** section before updating). Node.js 6.x, 8.x, 11.x support was removed. Now you need to install Autoprefixer by `npm install --save-dev autoprefixer postcss`. We moved `postcss` from `dependencies` to `peerDependencies` according to [new PostCSS plugin guidelines](https://togithub.com/postcss/postcss/blob/master/docs/guidelines/plugin.md).

---

Renovate configuration

:date: Schedule: "every weekday" (UTC).

:vertical_traffic_light: Automerge: Enabled.

:recycle: Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

:no_bell: Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR has been generated by WhiteSource Renovate. View repository job log here.