Looking for WoW Classic patch notes.
Are you talking about the current beta version of classic? or previous patches in retail classic?
I don't think they're doing patch notes for the beta, only known issues: https://us.forums.blizzard.com/en/wow/t/wow-classic-beta-known-issues-list-6-4-19/173883
and the not a bug list: https://us.forums.blizzard.com/en/wow/t/wow-classic-not-a-bug-list/175887 .
Any updates will be on the official classic wow forum but they will be few and far between in terms of actual updates/patches. https://us.forums.blizzard.com/en/wow/c/in-development/wow-classic-beta-test