[xmonad] Maintainership handover: welcome Adam Vogt

[Don Stewart]

Hey all,

Just to let the community know: over time Spencer and I have had less
and less time to coordinate releases and maintain the core of xmonad.
Thankfully, we have a large group of excellent, active contributors.

The time has come to recognize the bottlenecks are me and Spencer, and
as a result, I'd like to announce that Adam Vogt has been added as a
committer to the core system, with authority to coordinate releases and
uploads to Hackage.

Expect progress now on the GHC 7 support release, as Adam works with the
team to schedule the release.

Thank you Adam, for stepping up!

-- Don Stewart