proposed 8.0 cycle freeze/release dates

[Peter Maydell]

Here's my proposal for 8.0 cycle freeze and release dates:

https://wiki.qemu.org/Planning/8.0

2022-12-14 : Beginning of development phase
2022-03-07 : 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.
2022-03-14: Hard feature freeze. Tag rc0
2022-03-21: Tag rc1
2022-03-28: Tag rc2
2022-04-04: Tag rc3
2022-04-11: Release; or tag rc4 if needed
2022-04-18: Release if we needed an rc4

thanks
-- PMM