Add repositories from project.clj to deps.edn

[dakra]

I'm not really familiar with leinigen so not sure if :mvn/repos in deps.edn is the same as :repositories in project.clj.

E.g. the :repositories key like here could then end up in deps.edn like:

:mvn/repos {"confluent" {:url "https://packages.confluent.io/maven/"}} ?

[borkdude]

Seems like a good thing to add, PR welcome