bcoin: switch to node@14
bcoin: switch to node@14

This may be compatible with Node 16. However, it seems less wasteful of
CI resources to switch this to Node 14 first and back to Node 16 later,
rather than re-run #75595 with a revision bump to `bcoin`.

Closes #75704.

Signed-off-by: Michka Popoff <5d406f95fb0e0230f83654e4a22d0115cc205d59@users.noreply.github.com>
Signed-off-by: BrewTestBot <8a898ee6867e4f2028e63d2a6319b2224641c06c@users.noreply.github.com>

cblecker/homebrew-core,Linuxbrew/homebrew-core,makigumo/homebrew-core,adam-moss/homebrew-core,uyjulian/homebrew-core,zyedidia/homebrew-core,Linuxbrew/homebrew-core,adam-moss/homebrew-core,filcab/homebrew-core,nandub/homebrew-core,nbari/homebrew-core,nandub/homebrew-core,uyjulian/homebrew-core,chrisfinazzo/homebrew-core,mfikes/homebrew-core,Homebrew/homebrew-core,stgraber/homebrew-core,zyedidia/homebrew-core,mbcoguno/homebrew-core,chrisfinazzo/homebrew-core,lemzwerg/homebrew-core,filcab/homebrew-core,lemzwerg/homebrew-core,sjackman/homebrew-core,JCount/homebrew-core,Homebrew/homebrew-core,mbcoguno/homebrew-core,stgraber/homebrew-core,Moisan/homebrew-core,mbcoguno/homebrew-core,nbari/homebrew-core,mfikes/homebrew-core,makigumo/homebrew-core,Moisan/homebrew-core,JCount/homebrew-core,sjackman/homebrew-core,cblecker/homebrew-core