Create 9.0.1 with EGL and OSMesa on branch

[basnijholt]

Checklist

• [x] Used a personal fork of the feedstock to propose changes
• [x] Bumped the build number (if the version is unchanged)
• [x] Reset the build number to 0 (if the version changed)
• [x] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [x] Ensured the license file is being packaged.

I have put a lot of work into getting VTK with EGL and VTK in https://github.com/conda-forge/vtk-feedstock/pull/225.

Unfortunately, I need to be able to simultaneously install FreeCAD and VTK with EGL but because FreeCAD is only built with VTK 9.0.1 and conflicts prevent me from updating FreeCAD to support 9.1.0, see https://conda-forge.org/status/#other_migrations.

This is because SMESH does not support OCCT 7.6 and OCCT 7.5 is only built with VTK 9.0.1.

Therefore, I have created a branch 9.0.1 from master where this PR will be merged into.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[basnijholt]

@matthiasdiener any objections?

[matthiasdiener]

@matthiasdiener any objections?

No objections from me (although I'm not familiar with this way of building an older version of a package).

[basnijholt]

This is the way to maintain older versions https://conda-forge.org/docs/maintainer/updating_pkgs.html?highlight=branch#maintaining-several-versions

Otherwise, it's nothing special.

Think we can merge this?

[matthiasdiener]

https://conda-forge.org/docs/maintainer/updating_pkgs.html?highlight=branch#maintaining-several-versions

I see, thanks. I guess it's fine to merge this.

[Tobias-Fischer]

@basnijholt - do you want to add that branch to the ABI migration branches?

[basnijholt]

That might be nice but I'm AFK until February.