Update DEPLOY.md as proposed in #1890

[j-cr]

This is a tiny documentation change that can save newcomers some googling. With the proposed change, the confusing error described in #1890 won't be encountered by those who follow the DEPLOY.md docs.

See #1890 (comment)

marick commented on Jan 23, 2016
For people finding this page via a search for "No connector available to access repository snapshots" lein leiningen who are also inexpert in things Maven-ey:

This is an error message you can get by deploying a major-minor-tiny-SNAPSHOT version to clojars via lein deploy when you don't have a ["snapshots" :clojars] entry in :deploy-repositories in your project.clj. If you make that latter look like the following, lein deploy will work:

[j-cr]

Ugh, sorry. Somehow I've messed this up; I'll close this pull request and create another, clean one.

(Note to self: don't use github's online editor. Especially if it's well past midnight.