Remove Python 3.8 and 3.9 support

[Saransh-cpp]

Python 3.8 has already been EOL for a while now and 3.9 will reach EOL this year. Moreover, I contributed a vector-numba (#600) functionality upstream to numba, but we cannot get rid of the local implementation and use numba's implementation as numba now only supports Python 3.10+. Hence, adoption of a new upstream feature is being blocked by vector's support of old Python versions, which is definitely a concern.

Blocked by #531