Bump sigstore/gh-action-sigstore-python from 3.0.1 to 3.1.0 (#918)

Bumps [sigstore/gh-action-sigstore-python](https://github.com/sigstore/gh-action-sigstore-python) from 3.0.1 to 3.1.0.
- [Release notes](https://github.com/sigstore/gh-action-sigstore-python/releases)
- [Changelog](https://github.com/sigstore/gh-action-sigstore-python/blob/main/CHANGELOG.md)
- [Commits](sigstore/gh-action-sigstore-python@v3.0.1...v3.1.0)

---
updated-dependencies:
- dependency-name: sigstore/gh-action-sigstore-python
  dependency-version: 3.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/publish-to-pypi.yaml

@@ -110,7 +110,7 @@ jobs:
           name: python-package-distributions
           path: dist/
       - name: Sign the dists with Sigstore
-        uses: sigstore/gh-action-sigstore-python@v3.0.1
+        uses: sigstore/gh-action-sigstore-python@v3.1.0
         with:
           inputs: >-
             ./dist/*.tar.gz