ci: run `deploy` workflow against branch

[leovct]

Description

Follow up of #143. The problem is that the workflow runs in the context of the main branch, which means it executes the workflow code, environment, and configurations from the main branch, not the changes introduced in the pull request branch. This pull request aims to modify the workflow to run against the code and changes present in the pull request branch, rather than the main branch context.

References (if applicable)

• https://dvc.ai/blog/testing-external-contributions-using-github-actions-secrets
• https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target

[rebelArtists]

@leovct have we tested ?

[leovct]

@leovct have we tested ?

yup it's already in place in the security-build job :)