When you get Root package X reference Y cannot be satisfied, I don't see anything in the logs (--vverbose) showing what caused this.
In my case it should show:
"gtk-d ~>3.4" violates "gtk-d:gtkd": "~>3.3.0" in gtk-d (and maybe show dependency chain)
"dependencies": {
"gtk-d" : "~>3.4",
"ggplotd": ">=1.1.2",
},