proposed schedule for 6.2 release

[Peter Maydell]

Draft schedule for 6.2. This is just starting from "don't want
a possibly-late release to get too close to xmas holiday season"
and working backwards.

2021-11-02 Soft feature freeze. Only bug fixes after this point.
           All feature changes must be already in a sub maintainer
           tree and all pull requests from submaintainers must have
           been sent to the list by this date.
2021-11-09 Hard feature freeze. Tag rc0
2021-11-16 Tag rc1
2021-11-23 Tag rc2
2021-11-30 Tag rc3
2021-12-07 Release; or tag rc4 if needed
2021-12-14 Release if we needed an rc4

Opinions?

-- PMM