*/*: Deprecate python2 consumers
lang/python2 and lang/python27 have been deprecated since 2020-01-01 and their
EXPIRATION_DATE of 2020-12-31 passed nearly six years.
Set the same expiration date on the remaining python:2.7 consumers so that
python2 and python27 can be removed on 2026-11-01
The date was chosen to fall after the 2026Q4 branch is created, so that the
removal happens on main only and the quarterly branch keeps python2 for its
full lifetime.
Approved by: portmgr