Change in HTTPbis chairs

Hi All,

After recently letting Barry know, I've got a little change in the HTTPbis
chairing status to share - we're going to shift to 2 chairs for the moment:
Mark and Tommy. When I shifted employers about a year ago the 3 chair
arrangement made sense to both avoid conflicts and provide some runway to
bring Tommy up to speed. Now that Tommy has just about a year of experience
under his belt as co-chair we can move to a 2 chair posture more
appropriate to the workload. Dare I say - Mission Accomplished - so I'll
happily step aside from this particular role for now...

I've learned quite a bit in my tenure and thank you all for the support
over that time  (not to mention the drafts, the PRs, the comments and hums.)

-Patrick