fix: bring back --up flag

[marco-m]

Desired Outcome

Fix #254 (flag --up is not working any more).

Implemented Changes

Describe how the desired outcome above has been achieved with this PR. In
particular, consider:

• What's changed? Why were these changes made?

Added back the handling of --up flag, which has been removed by mistake (I think).

• How should the reviewer approach this PR, especially if manual tests are required?

Best reviewed commit-per-commit, considering the commit messages.

No manual tests are required; the PR adds an integration test to protect from this regression. See the comments I added in #254 for details.

Connected Issue/Story

Resolves #254

Definition of Done

At least 1 todo must be completed in the sections below for the PR to be
merged.

Changelog

• The CHANGELOG has been updated, or
• This PR does not include user-facing changes and doesn't require a
  CHANGELOG update

Test coverage

• This PR includes new unit and integration tests to go with the code
  changes, or
• The changes in this PR do not require tests

Documentation

• Docs (e.g. READMEs) were updated in this PR
• A follow-up issue to update official docs has been filed here: [insert issue ID]
• This PR does not require updating any documentation

Behavior

• This PR changes product behavior and has been reviewed by a PO, or
• These changes are part of a larger initiative that will be reviewed later, or
• No behavior was changed with this PR

Security

• Security architect has reviewed the changes in this PR,
• These changes are part of a larger initiative with a separate security review, or
• There are no security aspects to these changes

[SpectreVert]

LGTM. The integration test is a good addition.