[3.12] gh-106967: remove Release and Date fields from whatsnew for 3.12 (#109648)

fix: remove Release and Date fields from whatsnew

python/release-tools template for "What's New" page automatically adds
a "Release" field and a "Date" field with the date set to "today", which
becomes the day the docs are built, which is forever increasing. This is
the topic of https://github.com/python/release-tools/issues/34 which is
yet to be fixed. In the meantime, this commit fixes it manually.

Co-authored-by: Oliver Rew <orew@bloomberg.net>