[CImGuiPack] Update to ImGui 1.90.8

[JamesWrigley]

Note that the URL changed in Gnimuc/CImGui.jl#119.

CC @Gnimuc

[Gnimuc]

Thanks for following this up!

We could also pick up LLVM.jl's way to support a local-build: https://github.com/maleadt/LLVM.jl/blob/master/deps/build_local.jl

I think we should also move CImGui.jl to JuliaImGui if more people are get involved in.

[JamesWrigley]

We could also pick up LLVM.jl's way to support a local-build: https://github.com/maleadt/LLVM.jl/blob/master/deps/build_local.jl

Hmm, yeah that could be useful 🤔

I think we should also move CImGui.jl to JuliaImGui if more people are get involved in.

Sure, that's fine with me 👍

[JamesWrigley]

(made this a draft for now because I think some more build changes are necessary)

[JamesWrigley]

I believe this is ready to merge now.

[JamesWrigley]

We could also pick up LLVM.jl's way to support a local-build: https://github.com/maleadt/LLVM.jl/blob/master/deps/build_local.jl

We have something like that now :) https://github.com/Gnimuc/CImGui.jl/blob/1.90.8/cimgui-pack/build.jl