update sigstore version (#121)

Author: jeremiah-kang

.github/workflows/publish-to-test-pypi.yml

@@ -190,7 +190,7 @@ jobs:
           path: dist/
 
       - name: Sign Distribution
-        uses: sigstore/gh-action-sigstore-python@v2.1.1
+        uses: sigstore/gh-action-sigstore-python@v3.4.0
         with:
           inputs: |
             ./dist/*.tar.gz