Drop bullseye support

[legoktm]

Status

Ready for review (needs infra help)

Description

This is split into two commits for ease of review and future git blame.

Drop bullseye support

We are moving to bookworm, so we can set Python 3.11 as the minimum
version to support and avoid installing poetry from pip.

There's one FIXME in the piuparts job because we don't have
bookworm on apt.freedom.press yet. Using the bullseye repository
should be fine for now.

Apply ruff fixes for Python 3.11

• Use T | None instead of Optional[T].
• Also use T | U instead of Union[T, U]
• Use new datetime.UTC as shorthand

Test Plan

• Visual review
• CI passes
• Needs infra to move "required" labels from bullseye jobs to bookworm equivalents

Checklist

If these changes modify code paths involving cryptography, the opening of files in VMs or network (via the RPC service) traffic, Qubes testing in the staging environment is required. For fine tuning of the graphical user interface, testing in any environment in Qubes is required. Please check as applicable:

• I have tested these changes in the appropriate Qubes environment
• I do not have an appropriate Qubes OS workstation set up (the reviewer will need to test these changes)
• These changes should not need testing in Qubes

If these changes add or remove files other than client code, the AppArmor profile may need to be updated. Please check as applicable:

• I have updated the AppArmor profile
• No update to the AppArmor profile is required for these changes
• I don't know and would appreciate guidance

If these changes modify the database schema, you should include a database migration. Please check as applicable:

• I have written a migration and upgraded a test database based on main and confirmed that the migration is self-contained and applies cleanly
• I have written a migration but have not upgraded a test database based on main and would like the reviewer to do so
• I need help writing a database migration
• No database schema changes are needed

[rocodes]

Thanks for preparing this. LGTM and have added 2 small docs PRs to accompany this change. LGTM, pending infra assistance.

[legoktm]

"Required" jobs has been updated on the infra side, so going to merge!