Announce the release

After svnpubsub has updated, the artifacts will be visible at https://www.apache.org/dist/brooklyn/, and distributed to Apache mirrors around the world shortly after.

An announcement email can then be made:

Subject: [ANNOUNCE] Apache Brooklyn 0.9.0 released

The Apache Brooklyn team is proud to announce the latest release of Apache
Brooklyn 0.9.0.

Apache Brooklyn is a framework for modelling, deploying, and managing
applications through autonomic blueprints. More details on Apache Brooklyn
can be found at https://brooklyn.apache.org/

Version 0.9.0 is a major step for Apache Brooklyn, including many new features
and fixes.

Thanks go to our community for their improvements, feedback and guidance, and
to Brooklyn’s commercial users for funding much of this development.

As well as a source code release, we offer a full binary distribution
download, and a full set of Maven artifacts for developers.

Release notes:
https://brooklyn.apache.org/v/0.9.0/misc/release-notes.html

Download:
https://brooklyn.apache.org/download/

User guide:
https://brooklyn.apache.org/v/0.9.0/

Maven artifacts have also been made available on repository.apache.org and
Maven Central.

Thanks
Richard Downer
release manager for 0.9.0
on behalf of the Brooklyn PPMC