Automatically namespace artifacts in deps.edn

[nivekuil]

As un-namespaced artifacts are now deprecated.

Before submitting a PR make sure the following things have been done (and denote this by checking the relevant checkboxes):

• [n/a] The commits are consistent with our contribution guidelines
• [X] You've added tests (if possible) to cover your change(s)
• [X] The new code is not generating byte compile warnings (run cask exec emacs -batch -Q -L . -eval "(progn (setq byte-compile-error-on-warn t) (batch-byte-compile))" clj-refactor.el)
• [no, see Scenario: Move forms does not create circular dependencies, #341] All tests are passing (run ./run-tests.sh)
• [ ] You've updated the changelog (if adding/changing user-visible functionality)
• [ ] You've updated the readme (if adding/changing user-visible functionality)

Thanks!

[expez]

Thanks @nivekuil! :100: