> how to specify specific version of package, e.g. opengl 1.2.3 in nimble file?
Nimble's github page doesn't show this, but according to [the source](https://github.com/nim-lang/nimble/blob/master/src/nimblepkg/version.nim): requires "opengl 1.2.3" Run or requires "opengl == 1.2.3" Run
