They posted this 11 days ago.
And this
https://twitter.com/Diablo?ref_src=twsrc^google|twcamp^serp|twgr^author
And this
UPDATE JUNE 8TH - Season 20 will be ending on June 21st. See post for exact times for each region.
https://us.diablo3.com/en/blog/23319442/season-20-now-live-2-28-2020?blzcmp=app
And this