buster EOL (10.13) and 11.5 planning

Hi,

Use of buster-security will pass from the Security Team to LTS in a few
days time, so we should get the EOL point release organised. We need at
least a couple of weeks to get things sorted, so as some suggestions:

- August 20
- [August 27 doesn't work for at least me and the Images Team, so nope]
- September 3rd
- September 10th

We're currently only 3 weeks past the 11.4 bullseye point release, but
that was also about 6 weeks late. It's therefore worth considering
whether we want to try and get 11.5 out sooner and get back onto the
previous track, or delay it a little more and aim for every two months
from 11.4's release date.

tl;dr - please indicate your availability / preferences for the above
dates (for both 10.13 and 11.5) and any opinions on whether we should
do them at the same time or separately.

Thanks,

Adam