ci: bump sigstore-python action to fix deprecation (#184)

Author: deepyaman

.github/workflows/publish.yml

@@ -66,7 +66,7 @@ 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@v3.0.1
         with:
           inputs: >-
             ./dist/*.tar.gz