Cyrus release process - switching to odd-even release cycle

[ellie timoney]

Hi :)

We've been talking about how we manage Cyrus releases, and the
increasing gulf between the 3.0 series and the master branch --
accompanied by vague second-hand memories of the 2.4->2.5->3.0
transitions...

As of now, we're switching to an odd-even release cycle.

The 3.0.x series will continue to be our stable series -- there is no
change here.  If you are a package maintainer of some sort, we recommend
tracking this series.

In maybe the next week or so, we will make our first release from the
unstable 3.1 series.  3.1.x releases will only ever be snapshots of the
master branch, and should be considered for testing purposes and
bleeding-edge features only.  We will try to release these snapshots at
coherent development points, but there will generally be large breaking
changes occurring between releases in this series.

At some point in the distant future, the next stable release series will
be 3.2, which will aim to include the stabilised versions of the
features developed/tested in the 3.1 releases.

Cheers,

ellie