Bump sigstore/gh-action-sigstore-python from 2.1.1 to 3.0.0 (#326)

Author: dependabot[bot]

.github/workflows/docker-publish.yml

@@ -144,7 +144,7 @@ jobs:
                 name: python-package-distributions
                 path: dist/
           - name: Sign the dists 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 ./dist/*.whl