conda-souschef is unable to parse recipes with microarch-level

[matthewfeickert]

In conda-forge/pythia8-feedstock#52 (comment) and conda-forge/awkward-cpp-feedstock#57 (comment) the conda-forge linter is leaving the feedback on valid recipes that use the microarch-level helper packages (c.f. conda-forge Knowledge Base docs on "Microarchitecture-optimized builds") that

For recipe/meta.yaml:

• ℹ️ The recipe is not parsable by parser conda-souschef (grayskull). Your recipe may not receive automatic updates and/or may not be compatible with conda-forge's infrastructure. Please check the logs for more information and ensure your recipe can be parsed.

I believe that the recipes are valid, so I think this is a bug. I'm happy to help investigate however I can.