fix: test.pypi.org workflow environment name

[marksweb]

Description

Just noticed the environment name didn't match the standard setup for our pypi.org vs test.pypi.org publishing.

Checklist

• [x] I have opened this pull request against master
• [ ] I have added or modified the tests when changing logic
• [x] I have followed the conventional commits guidelines to add meaningful information into the changelog
• [x] I have read the contribution guidelines and I have joined #workgroup-pr-review on Slack to find a “pr review buddy” who is going to review my pull request.