Bump sigstore/gh-action-sigstore-python from 1.2.3 to 2.1.0

Bumps [sigstore/gh-action-sigstore-python](https://github.com/sigstore/gh-action-sigstore-python) from 1.2.3 to 2.1.0.
- [Release notes](https://github.com/sigstore/gh-action-sigstore-python/releases)
- [Commits](sigstore/gh-action-sigstore-python@v1.2.3...v2.1.0)

---
updated-dependencies:
- dependency-name: sigstore/gh-action-sigstore-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/publish.yaml

@@ -68,7 +68,7 @@ jobs:
         name: python-package-distributions
         path: dist/
     - name: Sign the dists with Sigstore
-      uses: sigstore/gh-action-sigstore-python@v1.2.3
+      uses: sigstore/gh-action-sigstore-python@v2.1.0
       with:
         inputs: >-
           ./dist/*.tar.gz