While the article might be from 1995, the library is still maintained. There have been releases each year since 2019, including one last month.
https://ap5.com/
Ah, thanks for the clarification. Quicklisp is very much maintained and is the de-facto standard method for installing Common Lisp packages :) Although there are alternatives, too - https://github.com/CodyReichert/awesome-cl#library-manager