Update maven-model and plexus-utils to latest (3.8.4, 3.4.1)
Update maven-model and plexus-utils to latest (3.8.4, 3.4.1)

The newer maven-model requires a newer plexus-utils.

clojars/clojars-web,tobias/clojars-web,clojars/clojars-web,tobias/clojars-web,ato/clojars-web,ato/clojars-web,tobias/clojars-web,clojars/clojars-web