sidekiq upgrade to 3.4.2

[eritiro]

sidekiq version upgraded from version 2.17.8 to version 3.4.2 this also includes its upgraded dependencies:

• celluloid (from 0.15.2 to 0.16.0)
• connection_pool (from 2.1.2 to 2.2.0)
• redis-namespace (from 1.5.1 to 1.5.2)
• timers (from 1.1.0 to 4.0.1)

and adding a new dependency:

• hitimes (1.2.2)