Reduce our deprecation cycle length to 3 months, from 6 months? #8417
Description
See https://github.com/pypa/pip/pull/5572/files#r200841762 for initial context.
The real question is, do we want/prefer a 3 month/1 release cycle over a 6 month/2 release cycle? :)
Originally posted by @pradyunsg in https://github.com/pypa/pip/pull/5572/files