chore(python): use python 3.10 for docs build#282

Linchin merged 2 commits intomaingoogleapis/python-db-dtypes-pandas:mainfrom

owl-bot-update-lock-52210e0e0559f5ea8c52be148b33504022e1faef4e95fbe4b32d68022af2fa7egoogleapis/python-db-dtypes-pandas:owl-bot-update-lock-52210e0e0559f5ea8c52be148b33504022e1faef4e95fbe4b32d68022af2fa7eCopy head branch name to clipboard