Add TestPyPI publishing workflow for release PRs #108

[AdityaGupta716]

Closes #108

Adds a new workflow that publishes to TestPyPI every time a PR targeting main is opened or updated.

Changes:

• Added publish-to-testpypi.yml workflow that builds the package and publishes to TestPyPI on release PRs
• Uses trusted publishing (id-token: write) same as the existing PyPI workflow
• Only triggers on PRs to main, keeping it specific to release PRs

Note: A TestPyPI trusted publisher needs to be configured by a maintainer at test.pypi.org for this workflow to work.

[AdityaGupta716]

Hey @MakisH @IshaanDesai, plz review! TestPyPI trusted publisher needs to be configured at test.pypi.org by a maintainer for the workflow to actually run

[precice-bot]

This pull request has been mentioned on preCICE Forum on Discourse. There might be relevant details there:

https://precice.discourse.group/t/gsoc-2026-aditya-gupta/2773/1

[IshaanDesai]

Thanks for the contribution. The intention of publishing on TestPyPI after releasing is to ensure that the release to PyPI is successful. Keeping this in mind, can you please check whether we can configure the release.yml workflow to run only after publish-to-testpypi.yml succeeds?

Also, please take a look at the release.yml workflow and use the latest versions of the actions.

[AdityaGupta716]

@IshaanDesai hi, addressed both comments, Restructured release.yml so PyPI publish only runs after publish-to-testpypi succeeds via needs, and updated all action versions to match the rest of the repo.