2 week development freeze begins today

[Quentin Young]

Hi all,

FRR is trying out a new release procedure starting with the next release. The plan is this:

- 6 weeks prior to release, we'll freeze the `master` branch from allowing new feature PRs to be merged. Bugfix PRs will still be permitted during that time.
- 2 weeks after the freeze, we'll pull a release branch and also tag that branch as RC1. `master` will be unfrozen at that time.
- 2 weeks after that, we will tag RC2.
- 2 weeks after that we'll do the full release.

Consistent with this plan we're freezing master for features starting today. It will reopen for feature work in 2 weeks.

Quentin