Release and deploy version 0.5.2

[rafatower]

For consistency and to have a patch both in on-prem and clouds, generate a new version, test and deploy it.

[rafatower]

Already generated, tagged and tested in staging: https://github.com/CartoDB/crankshaft/releases/tag/0.5.2

cc/ @rporres

[rporres]

thx, @rafatower