[PROPOSED]: New JDK Updates Maintainer process

[Rob McKenna]

- After tagging the source code for the last planned update release in the
  forest they maintain, a maintainer should announce to the
  jdk-updates-dev mailing list that they plan to step down, provide a
  timeframe detailing when they intend to step down and call for a new
  maintainer of the forest.

  For example, the current set of jdk9u forest maintainers from Oracle now
  plan to maintain the jdk9u forest until March 2018. The project page
  will be updated to reflect this shortly.

- Suitable maintainers will be added to the OpenJDK JDK Updates Project
  page [1] by the project lead under the maintainers heading and with a note
  detailing the forests which they maintain.

- Maintainers of a JDK Updates forest may specify alternative codereview &
  approval mechanisms.

    -Rob

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