Bump cheshire in boot/worker to 5.6.0

This forces the jackson.databind transitive dependency to be bumped
up to 2.6, in order to fix compatability issues with s3-wagon-private.

Author: lsnape

boot/worker/project.clj

@@ -22,7 +22,7 @@
                  [net.cgrand/parsley          "0.9.3" :exclusions [org.clojure/clojure]]
                  [mvxcvi/puget                "1.0.1"]
                  [reply                       "0.3.7"]
-                 [cheshire                    "5.3.1"]
+                 [cheshire                    "5.6.0"]
                  [clj-jgit                    "0.8.0"]
                  [clj-yaml                    "0.4.0"]
                  [javazoom/jlayer             "1.0.1"]