juju-core 1.12 stable release

[David Cheney]

Hi Nick,

I wanted to give a heads up that I've created a new series for
juju-core, 1.12, which will be the stable release branch. This release
was branched from 1.11.4. This release obviously rolls up all the
changes since 1.10.x (which will be quite a large set), but
specifically

* contains an experimental local provider
* contains an experimental azure provider

With specific reference to the local provider, if people report issues
with it, we are unlikely (in general) to backport those fixes to the
stable release. Instead we would encourage people who want to follow
the development of the local provider to move to the development,
1.13.x branch and PPA. The next stable release, probably 4-6 weeks
out, 1.14 will list the local provider as its headline feature.

Cheers

Dave