{:deps {foo {:mvn/version "0.1.0"}
        bar {:mvn/version "0.2.0"}
        ;; here's a comment and the next dep is ignored:
        #_baz #_{:mvn/version "0.3.0"}}}

(require '[borkdude.rewrite-edn :as r])

(def edn-string (slurp "deps.edn"))

(def nodes (r/parse-string edn-string))

(println (str (r/assoc-in nodes [:deps 'my-other-dep] {:mvn/version "0.1.2"})))

{:deps {foo {:mvn/version "0.1.0"}
        bar {:mvn/version "0.2.0"}
        ;; here's a comment and the next dep is ignored:
        #_baz #_{:mvn/version "0.3.0"}
        my-other-dep {:mvn/version "0.1.2"}}}

(defn qualify-sym-node [sym-node]
  (let [sym (r/sexpr sym-node)]
    (if (or (not (symbol? sym))
            (qualified-symbol? sym))
      sym-node
      (symbol (str sym) (str sym)))))

(def updated-nodes (r/update nodes :deps #(r/map-keys qualify-sym-node %)))
(println (str updated-nodes))

{:deps {foo/foo {:mvn/version "0.1.0"}
        bar/bar {:mvn/version "0.2.0"}
        ;; here's a comment and the next dep is ignored:
        #_baz #_{:mvn/version "0.3.0"}}}