Add support for node v20

Hello there! I recently did a server upgrade, moving from node v18 to node v20, as that is now the latest release. I found out shortly after, however, that Ghost doesn’t have any support for node v20, and I had to downgrade back to v18 in the meantime.

I’ve seen some things about v20 support being worked on, but I figured I would ask and see if this is something that is coming soon. I looked at the roadmap, and v18 has left its active state and has been moved to only maintenance.

Thank you, and I hope for a response soon.

Voted for this, because I’m a big fan of updating to be “current” and staying on that leading edge, and “fixing forward” if there’s problems.

I’d also support moving straight to 22 given v20 is only going to be the main active version for another 8 months, but I realise it’s also about dependencies and the actual things that will no-doubt break along the way, I’m definitely pragmatic about that bit.

I’ve got a server on Node 16 that needs a dist-upgrade (ugh) to get to Node 18. If Ghost support for v20 is coming soon, I’d prefer to stall a little longer rather than signing up for this kind of fun twice.

(Yeah, I don’t think distribution upgrades are fun.)