5.1 proposed schedule

[Peter Maydell]

Here's a draft schedule for 5.1:

2019-07-06: softfreeze
2019-07-14: hardfreeze, rc0
2019-07-21: rc1
2019-07-28: rc2
2019-08-04: rc3
2019-08-11: release, or rc4 if we need it
2019-08-18: release if we needed an rc4

Does that work for people? I don't think there's anything we
particularly need to try to shift the schedule to avoid but
we can easily move it back or forwards by a week or so.

thanks
-- PMM