fix: upgrade gh-action-sigstore-python to v3.0.0

Author: shenxianpeng

source/guides/github-actions-ci-cd-sample/publish-to-test-pypi.yml

@@ -68,7 +68,7 @@ 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