Fix security issues with the Trusted Publishing example

https://github.com/simonw/python-lib/blob/4b825ed/%7B%7Bcookiecutter.hyphenated%7D%7D/.github/workflows/publish.yml#L44-L49 suggests that building the dists within the same job that publishes them is okay. But it's not.
Such a structure opens the workflow users to privilege escalation through poisoning the build dependencies, which is why I've always insisted on the separation — the build scripts must never have access to id-token: write.

• https://packaging.python.org/en/latest/guides/publishing-package-distribution-releases-using-github-actions-ci-cd-workflows/
• https://docs.pypi.org/trusted-publishers/security-model/

Another suggestion is to fix the GitHub Environment name to represent the deployment target as it's meant to. I usually go for pypi and testpypi so it's obvious that uploading to both is separate.

I saw release here https://github.com/simonw/python-lib/blob/4b825ed/%7B%7Bcookiecutter.hyphenated%7D%7D/.github/workflows/publish.yml#L33C5-L33C25, which is not an upload target but a process name which is very generic.

The declaration syntax can also be extended to include a URL:

-     environment: release
+     environment:
+       name: pypi
+       url: https://pypi.org/project/{% endraw %}{{ cookiecutter.hyphenated }}{% raw %}/${{ github.ref_name }}

Start with {{cookiecutter.hyphenated}}/.github/workflows/publish.yml, especially lines 33 and 44-49, then read the linked PyPI Trusted Publishing guidance. Check how the build and publish steps share permissions and how the release environment is named. Done means the workflow separates building from publishing, keeps id-token access away from build scripts, and names the PyPI targets with their project URL.