setup.py: Correct dependency on fido2
setup.py: Correct dependency on fido2

`yubikey-manager` depends on APIs introduced in `fido2` v0.7.0.
If `fido2` follows semantic versioning conventions, this ought to be `fido2 ~= 0.7.0`.
Yubico/yubikey-manager,Yubico/yubikey-manager