[12u-communication] End of maintenance & invitation for new maintainers

[Rob McKenna]

I'm sending this mail to notify the community that the current maintainers
intend to step down as maintainers for the JDK 12 Updates forest [1] at the
end of September.

This being the case we would like to invite prospective new maintainers to step
forward at this point to ensure a smooth transition should they wish to
maintain this forest beyond the end of September.

     -Rob

[1] http://hg.openjdk.java.net/jdk-updates/jdk12u