Add bounds to BangBang/Compat.toml

[tkf]

This patch adds (upper) bounds to BangBang/Compat.toml so that old versions will not be installed in the future when the latest versions do not support some set of upstream versions. (As discussed in https://discourse.julialang.org/t/backpropagate-compat-bounds/30737/5)

I tried to mimic how Compat.toml is "compressing" the bounds but I'm not sure if I did it correctly. Would RegistryCI find incorrect bound specification?

[fredrikekre]

Would RegistryCI find incorrect bound specification?

It checks that Pkg can actually read the bounds, but not if they "make sense".

Edit: Needs a rebase.

[tkf]

Thanks. I resolved the conflict.

but not if they "make sense"

I think it would be nice if the CI can check that the compat bound is not tightened than the existing versions (i.e., it's "no-op"). Is it hard to verify this? If I were to feature request it, should it go to RegistryCI.jl? Or maybe to Pkg.jl to add some kind of Pkg.Registry.* API to create the correct Compat.toml in the first place?

[fredrikekre]

We should probably have a package/repo for modification of registry files. Right now it is split up over Pkg/bin and Registrator, but neither place is a good fit IMO.