uprev and generate history

release notes for v1 (pydantic#918)

* release notes for v1

* uprev and tweaks

* Apply suggestions from code review

Co-Authored-By: dmontagu <[email protected]>

* tweak notes, add back link to old docs

* build changelog

prepare v1.0b2

Version 1 beta (pydantic#853)

* link to old docs, uprev

* generate history

uprev

uprev

uprev

uprev

uprev

uprev