Update publish.yaml

[AnesBenmerzoug]

Description

This PR adds missing env variables to the publish CI job
that prevented pushing new docs.

Hopefully with this fix we can trigger the deployment of a new PyPI package using the develop branch's CI file.

Changes

• Defined GITHUB_BOT* env variable in publish workfloa.

Checklist

• Wrote Unit tests (if necessary)
• Updated Documentation (if necessary)
• Updated Changelog
• If notebooks were added/changed, added boilerplate cells are tagged with "tags": ["hide"] or "tags": ["hide-input"]

[mdbenito]

Sorry, I’m lost here. Why is that env var necessary and what problem are we trying to solve?

[AnesBenmerzoug]

Those 2 env vars represent the Github Bot user. They are used when pushing a new version of the docs to the gh-pages branch and since they were missing it was always failing. I didn't notice it before because they were just passed as empty strings (default for undefined env vars).