I apologize for any confusion my joke caused; I thought it was clear that it was a joke, but evidently not!
It seemed worthwhile to note that users shouldn’t have expected to see a 1.13.0-alpha1 release but would see a 1.13.0-alpha1 tag in the repository. The actual reasons why are not particularly interesting or generally relevant (e.g., a bug in code that only gets executed on release builds, among a series of other random things) so it seemed like an opportunity to add a bit of Julia-related humor, which I’ve done previously as well.
I do love to make jokes, though I can’t claim to make good ones. 
But perhaps I could be a bit more judicious in where I make them.