That's not true. https://status.heroku.com shows that the incident is ongoing, that they've disabled the GitHub integration, and don't have plans to reenable it until full assessment is complete
You have to actually click on the general advisory of the email from Salesforce (which isn't obviously actually useful to click, there's no arrows indicating it'll expand or anything) and then you have to scroll down to an entry which isn't signposted.
Additionally, in two browsers, if I clicked to expand it, then clicked the 'back to current status' button, it errored out with the console full of errors and couldn't be clicked again, which doesn't fill me with too much confidence.
What a mess. I have fond memories of Heroku (or rather, how little I had to think about anything deployed to it. Liberating.)