Bug: existing tags are not updated

During the release of `v0.1.1` of the HTTP gateway, the first release failed to publish to crates.io due to not being an owner: https://github.com/holochain/hc-http-gw/actions/runs/16118822647/attempts/1

This is as expected, but when given owner permissions and re-running the release workflow, it failed again because the tag already existed and couldn't be updated due to:

> cannot push because a reference that you are trying to update on the remote contains commits that are not present locally

see: https://github.com/holochain/hc-http-gw/actions/runs/16118822647/attempts/2

Deleting the tag and re-re-running the workflow then worked, but I'm not sure where these extra commits came from and why we can't update the tags, so this needs looking into.