Upgrade to release 0.21.4:
- Explicitly declare support for Python 3.10 as well as some minor
internal improvements.
Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Trevor Gamblin <trevor.gamblin@windriver.com>