Contents of the :is and :where pseudo-class functions is not optimized about csso

[lahmatiy]

Thank you for the issue!
Used old version of CSSTree which parses a content of :is()/:where() as a single block. That's not a problem for a specificity computation, but a problem for optimisations.
CSSTree was bumped to the latest version v2.2.0. It should fix the issue. Please, upgrade to CSSO v5.0.5.

[lahmatiy]

@pepelsbey You can re-install postcss-csso (or upgrade csso directly), and npm will install latest csso since postcss-csso v6.0.0 used to use ^5.0.1.
However, for convenience I've just published postcss-csso v.6.0.1 with csso: ^5.0.5 on board.

[pepelsbey]

@lahmatiy thank you for the fix! Do you mind updating the postcss-csso plugin’s deps? It still uses v5.0.1. It’s very convenient to use CSSO as one of the PostCSS plugins.