0.50400.0 release?

[SDGGiesbrecht (Jeremy David Giesbrecht)]

This is a friendly reminder that it’s release time again and a 0.50400.0 tag would be appreciated for swift-syntax and swift-format.

@allevato, @akyrtzi

[akyrtzi (Argyrios Kyrtzidis)]

Done for swift-syntax!

[allevato (Tony Allevato)]

The 0.50400.0 release of swift-format is now also up!