leiningen: Update to 2.1.2

Signed-off-by: Moritz Ulrich <moritz@tarn-vedra.de>
Add myself (the-kenny) to the maintainer list.

Signed-off-by: Moritz Ulrich <moritz@tarn-vedra.de>
Merge pull request #428 from the-kenny/leiningen

Leiningen: Update to 2.1.2