ci: release-plz fails on CI

[aborgna-q]

#644 seems to have broken the release-plz workflow, though I'm not sure why.

Caused by:
    0: failed to determine next versions
    1: failed to retrieve difference between packages
    2: The allow-dirty option can't be used in this case
    3: error while running git in directory `"/tmp/.tmpSdMB4E/tket2"` with args `["checkout", "295b0df1a01a58d46b3787c49082d2b6dbe3ccb9"]:
       - stderr: error: Your local changes to the following files would be overwritten by checkout:
       	Cargo.lock
       Please commit your changes or stash them before you switch branches.
       Aborting

https://github.com/CQCL/tket2/actions/runs/11270110079/job/31340128460#step:4:236

The error is consistently failing all workflow runs since.

[aborgna-q]

This was an internal bug in release-plz. I did the last release with a locally patched version, and it should work correctly from now on.