build(deps-dev): bump rollup-plugin-postcss from 2.0.3 to 2.0.4 (#644)

Bumps [rollup-plugin-postcss](https://github.com/egoist/rollup-plugin-postcss) from 2.0.3 to 2.0.4.
- [Release notes](https://github.com/egoist/rollup-plugin-postcss/releases)
- [Changelog](https://github.com/egoist/rollup-plugin-postcss/blob/master/CHANGELOG.md)
- [Commits](egoist/rollup-plugin-postcss@v2.0.3...v2.0.4)

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

Author: dependabot-preview[bot]

yarn.lock

@@ -12234,9 +12234,9 @@ rollup-plugin-node-resolve@^5.2.0:
     rollup-pluginutils "^2.8.1"
 
 rollup-plugin-postcss@^2.0.3:
-  version "2.0.3"
-  resolved "https://registry.yarnpkg.com/rollup-plugin-postcss/-/rollup-plugin-postcss-2.0.3.tgz#1fd5b7e1fc7545cb0084d9c99d11b259e41a05e6"
-  integrity sha512-d12oKl6za/GGXmlytzVPzzTdPCKgti/Kq2kNhtfm5vv9hkNbyrTvizMBm6zZ5rRWX/sIWl3znjIJ8xy6Hofoeg==
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/rollup-plugin-postcss/-/rollup-plugin-postcss-2.0.4.tgz#da4e8ff43f4e1f45222decd193020bb5b8d8e583"
+  integrity sha512-rYOa1eF4MzSig7L4lFtc1hGdcue1dX4yjFbRjC5hFpcYMjTnwsC8Atny3nDg6ynGYPZk2EAiZMTjixp5TfQOxA==
   dependencies:
     chalk "^2.4.2"
     concat-with-sourcemaps "^1.0.5"