0.18 hasn't been released yet. Godot-nim appears to depend on devel (a.k.a v0.17.3 a.k.a the development version).
Easiest way to get devel is via choosenim
Leading version zeros smell of weakness. And real code warriors do regular release engineering, like OpenBSD.
I'd move the damn decimal point and call it version 18.xx. Release 19.xx next year.