try v1 recipe.yaml when bot migrators are ready

[minrk]

The newer v1 recipe.yaml format is slowly being adopted in conda-forge, which can be used with the much faster rattler-build, and I think this repo could benefit a lot from it because there are so many builds and the overhead of each build is significantly reduced.

But I don't think we should do it until the version-update bots have gained support for the new recipe format: conda-forge/conda-forge.github.io#2308

EDIT: in-progress PR: regro/cf-scripts#3525