CompatHelper: bump compat for ManifoldDiff to 0.4 for package tutorials, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the ManifoldDiff package from 0.3.9 to 0.3.9, 0.4 for package tutorials.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[kellertuer]

I am not really sure what is happening here. Maybe next week with a bit more sleep I try to understand the error message.

[mateuszbaran]

Manopt is marked as compatible with Colors 0.13 but Manifolds.jl isn't. Dependencies for tutorials are resolved in two steps so Colors 0.13 is picked but later Pkg figures out it can't it but it's to late to downgrade.

Simple solution: mark Manopt.jl as not compatible with Colors.jl until Manifolds.jl is compatible with it.

[kellertuer]

Oh I would never have read that from the error message provided. But we do have the PR for Manifolds already, so what is missing for that? I think I'll just keep this PR open then until Manifolds.jl is compatible then.

Just strange that this happens when bumping something completely different.

[mateuszbaran]

We have the relevant PR here: JuliaManifolds/Manifolds.jl#763 . Maybe PythonPlot.jl tagging a new release would be enough but I haven't checked if we have any other incompatibilities in Manifolds.jl.

[kellertuer]

In the long run we could maybe also move the plotting extension therein into a separate package, to have a bit less of these problems.

[dehann]

Hi, if there is a chance (Id add +1) to have plotting in weakdeps or as an option somehow. E.g. we avoid Python dependencies as far we can, previously used Gadfly and Plots but now moving to Makie.

[kellertuer]

Manopt.jl has plotting only as weak dependency.
Manifolds.jl does have a direct one I think.

It would probably still be best to unify all this – including the asymptote exports I wrote long time ago into a ManifoldPlots.jl (or a similar name) package.
Just that my list of things to do in open source by now is so long that I can not promise anything before summer (LieGroups.jl, robust LevenbergMarquardt, several collaborations, ...).