Update postcss-loader usage and config #11552
Description
According to their recent release the devs seem to be patching an unsupported usage of options within the webpack config. You can see this here.
We should update our webpack-common.js to support this change. A PR has been submitted to pin the version to v2.1.1 until we can figure out a solution.
Lets also not forget to add the ^ caret back as well.