Marking some more `nox` commands as external.
Marking some more `nox` commands as external.

See failures:

https://ci.appveyor.com/project/dhermes/bezier/build/job/y10ytkynyd6dxfs7
https://circleci.com/gh/dhermes/bezier/1394

dhermes/bezier,dhermes/bezier,dhermes/bezier