Bug#986993: release-notes: Mention OpenJDK 17 status in bullseye

[Matthias Klose <doko@debian.org>]

Package: release-notes
X-Debbugs-CC: Moritz Muehlenhoff <jmm@debian.org>

Please document the OpenJDK 17 status in bullseye:

Debian bullseye comes with an early access version of OpenJDK 17 (the next
expected OpenJDK LTS version after OpenJDK 11), to avoid the rather tedious
bootstrap process.  OpenJDK 17 will be updated in bullseye to the final upstream
release announced for October 2021.  Security updates for OpenJDK 17 are planned
on a best effort basis, but don't expect to see updates for every quarterly
upstream security update.