Proposing to release SIS 1.6

[Martin Desruisseaux via dev]

Hello all

I propose to release Apache SIS 1.6 this week. The SIS 1.5 release was 3 
months ago, but we have a security fix to publish and a faster cadence 
is desired anyway. This release includes an upgrade of EPSG geodetic 
dataset from 12.026 to 12.047. Is there any objection?

    Martin