Release 1.0.5 version

[EugeneTorap]

#155 (Removes upper bound for pyarrow) is already merged.
Can we release a new version of db-dtypes?

[EugeneTorap]

@tswast @parthea @chalmerlowe Can we do it?

[tswast]

Unfortunately the bot didn't pick #155 up due to the "chore" prefix. See: https://github.com/googleapis/release-please#release-please-bot-does-not-create-a-release-pr-why

I think our best option would be to send an empty PR detailing #155 as a deps: prefix with git commit --allow-empty -m "deps: remove upper bound on pyarrow version"

@EugeneTorap Would you mind sending one if I forget?

Edit: I've mailed #162

[tswast]

Fixed by #163