Bump clean-css from 4.2.1 to 4.2.2

Bumps [clean-css](https://github.com/jakubpawlowicz/clean-css) from 4.2.1 to 4.2.2.
- [Release notes](https://github.com/jakubpawlowicz/clean-css/releases)
- [Changelog](https://github.com/jakubpawlowicz/clean-css/blob/master/History.md)
- [Commits](clean-css/clean-css@v4.2.1...v4.2.2)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

yarn.lock

@@ -1585,9 +1585,9 @@ class-utils@^0.3.5:
     static-extend "^0.1.1"
 
 clean-css@^4.1.9:
-  version "4.2.1"
-  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.2.1.tgz#2d411ef76b8569b6d0c84068dabe85b0aa5e5c17"
-  integrity sha512-4ZxI6dy4lrY6FHzfiy1aEOXgu4LIsW2MhwG0VBKdcoGoH/XLFgaHSdLTGr4O8Be6A8r3MOphEiI8Gc1n0ecf3g==
+  version "4.2.2"
+  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.2.2.tgz#8519abda724b3e759bc79d196369906925d81a3f"
+  integrity sha512-yKycArwReQXbOD/3pmsPmt6p7oUBww8MisDabL2pCUWkbVONvCJoBdCjgY4ZVQmKX5juz/JB9oDcP6XzGUpjwQ==
   dependencies:
     source-map "~0.6.0"