Freeze v3

[Tom Zeller]

As discussed on the dev call, please consider the v3 stack, meaning
projects which inherit from the v3 parent POM, frozen at the end of
today.

End of today essentially means midnight. The Jenkins job which
produces v3 artifacts is scheduled to run starting at 1am EST, so
frozen artifacts will be available over the weekend.

We chatted about reserving Monday (the 22nd) for contingencies before
more folks are out for the holiday week. So, tagging and deploying to
the Nexus repository should happen on Sunday (the 21st).

Please let us know if there are concerns or questions.