Can't seem to find the relevant documentation for dub.

[WhatMeWorry]

I've got a pretty straightforward SDL dub file
dependency "bindbc-opengl"    version="~>1.0.3"
versions "GL_46"
dependency "bindbc-glfw"      version="~>1.0.1"
versions "GLFW_33"
dependency "gl3n"             version="~>1.4.1"
dependency "bindbc-freeimage" version="~>0.1.1"
versions "FI_317"


Unresolvable dependencies to package bindbc-loader:
   bindbc-freeimage 0.1.1 depends on bindbc-loader ~>0.2.1
   bindbc-freeimage 0.1.1 depends on bindbc-loader ~>0.2.1
   bindbc-glfw 1.0.1 depends on bindbc-loader ~>1.0.0
   bindbc-glfw 1.0.1 depends on bindbc-loader ~>1.0.0
   bindbc-opengl 1.0.3 depends on bindbc-loader ~>1.0.0
..\duball.exe exited with code 2


How to I tell dub that I want some packages to use different 
versions of the same package, bindbc-loader, in this case?