Coordinating the build number for 11.0.3

[Gil Tene]

As we approach the April update and the release of 11.0.3 by the
JDK11u project, I'd like to suggest a coordination of the eventual
build number that we expect to use for the actual released build in
the project (after integration of security fixes that are being worked
on in the dark).

Since the build number is a part of the versions string per JEP 322,
and since this is the most specific part of the version string that is
common across the various binary distributions (e.g.
Azul Zulu, AdoptOpenJDK, Corretto, Liberica, Red Hat, etc.), it
is useful for us all to use the same build number when we release
the first build of a new update of 11u. This has been the practice in
the past. E.g. for 11.0.2, we all aligned on the same "build 11.0.2+9"
in the version string.

Since the update itself is time sensitive, and it is useful to commence
testing ahead of time, knowing the build number to use in the builds
we test would be helpful in getting the builds ready to go ASAP once
the release is finalized.

So, I propose that we pre-choose a build number for the anticipated
April release of 11.0.3. I have no strong opinions on what that number
should be. It should probably not overlap with past or current builds of
11.0.3 in 11u, and "leaving room" (a gap of a few integer spaces
between the current build numbers and the anticipated one) is probably
a good idea.

— Gil.