Bump voluptuous (and other deps), support python 3.9+3.10

[ahayworth]

• Loosen voluptuous requirement
• Loosen mypy dev requirement
• Run poetry update
• Add CI support for python 3.9 and 3.10

[epenet]

Looks like you need to bump pytest also: https://stackoverflow.com/questions/69528842/an-error-while-trying-to-execute-tests-on-python-3-10-with-pytest

[ahayworth]

@epenet yes thank you, I was iterating on it and had just fixed this in c7b969bfcbfbb3871400452a2593f21c61e03fee.