ClojureScript itself is not affected. It uses very little of the library itself, which could easily be replaced if needed.

However, what might be affected is Projects/Libraries that use other things the Closure Library provides. While these things aren't going anywhere, they'll also receive no further updates. Given how mature and stable most of the things are that is fine, but may warrant starting to look for alternatives.

Given that there are very few things making actual use of goog.* stuff I'd say there is no meaningful impact to worry about.