Opush 3.0.6 release

Yet another Opush release today!

The new 3.0.6 adds a workaround that protect contact synchronization from duplication due to an Android issue not fixed by Google: see [the Android bug tracker](https://code.google.com/p/android/issues/detail?id=61100)

So, there is only one improvement brought by this version, the [server side contact duplication protection](http://ci-obm.linagora.com/jira/browse/OP-139).

# How to get it ?
To upgrade from a previous version of Opush follow [this section](http://docs.obm.org/opush/opush.html#_upgrades).Nike Air VaporMax 2019