Update node version that was breaking with upgrades to Github script

This updates from node 12 -> 18 LTS. There was an issue locally that I didn't detect until I tried to do a build where the current version 12 isn't supported by our updated packages, which I missed as I didn't have nvm active. While 18 is about to switch to maintenance, it's the current highest LTS we support. I've tested locally using NVM to go to v 18.16 and the scripts seem stable on run in dryrun/non-write mode.