In this sense "hacked" doesn't make sense. 8f everything was intended for open source.
Couldn't the "hacker" have simply generated a new GPG key and added it to the account he had control of?
This seems like a non-story.
One, this doesn't address exactly how the repo was compromised. Likely one of the many folks with access had their credentials compromised, but until we know, there may be risk to other projects. Two, as the article mentions, it may not have had all passwords or API keys scrubbed.