Bump clean-css from 4.1.3 to 4.1.11

Bumps [clean-css](https://github.com/jakubpawlowicz/clean-css) from 4.1.3 to 4.1.11.
- [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@v4.1.3...v4.1.11)

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

Author: dependabot[bot]

yarn.lock

@@ -969,8 +969,8 @@ clap@^1.0.9:
     chalk "^1.1.3"
 
 clean-css@4.1.x:
-  version "4.1.3"
-  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.1.3.tgz#07cfe8980edb20d455ddc23aadcf1e04c6e509ce"
+  version "4.1.11"
+  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.1.11.tgz#2ecdf145aba38f54740f26cefd0ff3e03e125d6a"
   dependencies:
     source-map "0.5.x"
 
@@ -3502,8 +3502,8 @@ source-map-support@^0.4.2:
     source-map "^0.5.6"
 
 source-map@0.5.x, source-map@^0.5.0, source-map@^0.5.3, source-map@^0.5.6, source-map@~0.5.1, source-map@~0.5.3:
-  version "0.5.6"
-  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.6.tgz#75ce38f52bf0733c5a7f0c118d81334a2bb5f412"
+  version "0.5.7"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
 
 spdx-correct@~1.0.0:
   version "1.0.2"