`:not` selector missing in 2.x

Originally reported in https://github.com/FullHuman/purgecss/issues/293#issuecomment-593420415

When reporting a bug, please try to include the following:

• A descriptive title
• An isolated way to reproduce the behavior (example: GitHub repository with code isolated to the issue that anyone can clone to observe the problem)
• What package and version you’re using, and the platform(s) you’re running it on: grunt-purgecss@2.1.1, purgecss@2.1.0

When you open an issue for a feature request, please add as much detail as possible:

• A descriptive title
• A description of the problem you’re trying to solve, including why you think this is a problem
• An overview of the suggested solution
• If the feature changes current behavior, reasons why your solution is better

.full-news a[href*="//"]:not([href^="mpc-hc.org"]):not([href*="trac.mpc-hc.org"])::after,
.new a[href*="//"]:not([href^="mpc-hc.org"]):not([href*="trac.mpc-hc.org"])::after {
    content: "\f08e"; /* fa-external-link */
    display: inline-block;
    font-family: FontAwesome;
    margin-left: 0.3em;
}

If change the code to this then it’s kept with the new version

.full-news a:not([href*="mpc-hc.org"])::after,
.new a:not([href*="mpc-hc.org"])::after {
    content: "\f08e"; /* fa-external-link */
    display: inline-block;
    font-family: FontAwesome;
    margin-left: 0.3em;
}

[luwes]

this one seems to be failing for me as well

:not(pre) > code {
  @apply text-sm text-red-600 bg-gray-100 p-1 rounded
}

[Ffloriel]

@pahan35 I’ll give it a try and let you know