Update version of signing action in GitHub Actions publishing workflow.

Author: lapets

.github/workflows/build-publish-sign-release.yml

@@ -63,7 +63,7 @@ jobs:
           name: python-package-distributions
           path: dist/
       - name: Sign the package distributions with Sigstore.
-        uses: sigstore/gh-action-sigstore-python@v2.1.1
+        uses: sigstore/gh-action-sigstore-python@v3.0.0
         with:
           inputs: >-
             ./dist/*.tar.gz