v0.2.1

Added

• A Thanks section in both READMEs. Three people outside the project have
  reported defects with the diagnosis, and often the fix. The section names what
  each report changed rather than listing handles: four releases come from
  @cedric-ribier (nominal disk sizes, libvirt 8,
  the Incus agent on AlmaLinux with a configurable host wait, and nested
  virtualization named), the conftest.py that silently blocked every shell lab
  from @Gedd18, and two labs whose starting state was
  unusable from @VictorVare.

  A credit that says what it fixed is worth more than a list, and it tells the next
  reader what kind of report is useful.