Updated "How the Working Group works"

Hi WPWG,

In light of our upcoming transition to “issue management mode” I took some time today to update:

 How the Working Group works
 https://github.com/w3c/webpayments/wiki/How-the-Working-Group-works

I have mostly tried to capture our current practices, and added a bit more about decisions (from our charter)
and issue management.

I welcome feedback and suggestions. I plan to speak about this briefly at this week’s teleconference.

In addition, I am looking into adjustments to the dashboard [1] to align with this updated material, and to
help us with agenda planning.

Ian

[1] https://waffle.io/w3c/webpayments
--
Ian Jacobs <ij@w3.org>      http://www.w3.org/People/Jacobs
Tel:                       +1 718 260 9447