bump to 0.5.0.0-RC

Changelog.md

-# Head
+# 0.5.0.0
 
 ## Major Sidekiq update
 This release includes a major upgrade of the background processing system Sidekiq. To upgrade cleanly:

config/defaults.yml

@@ -4,7 +4,7 @@
 
 defaults:
   version:
-    number: "head" # Do not touch unless doing a release, do not backport the version number that's in master but keep develop to always say "head"
+    number: "0.5.0.0" # Do not touch unless doing a release, do not backport the version number that's in master but keep develop to always say "head"
   heroku: false
   environment:
     url: "http://localhost:3000/"