fix: use PyPI trusted publisher authentication

[Bjarten]

Updates the GitHub Actions publish workflow to use PyPI's Trusted Publisher authentication instead of token-based authentication. This change improves security by:

• Removing the need to store PyPI tokens in GitHub secrets
• Using OpenID Connect (OIDC) for secure authentication
• Leveraging PyPI's recommended authentication method for GitHub Actions

Changes

• Removed token-based authentication (TWINE_USERNAME and TWINE_PASSWORD)
• Added required id-token: write permission for OIDC
• Switched from manual twine upload to pypa/gh-action-pypi-publish action