Clojure Leiningen update: add 2.5.0 and latest points to stable release

Ah, this one tags against the upstream "stable" branch?  That could potentially be different every time we build this, so I'd much rather this be hard-coded on 2.5.0 just like in https://github.com/Quantisan/docker-clojure/commit/27d0141c22bedbf78b908bf5bebd6629fc10a491, especially since each new upstream release would need to be a PR against this repo to add the new tag anyhow.  What do you think?