[ANNOUNCE] Michael Mior joins Calcite PMC

[Josh Elser]

I'm please to announce that Michael has accepted an invitation to join 
the Calcite PMC. Michael has been a consistent and helpful figure in the 
Calcite community for which we are very grateful. We look forward to the 
continued contributions and support.

Please join me in congratulating Michael!
- Josh (on behalf of the Calcite PMC)