ci: Delete Sigstore signing - PyPI already doing that

Only now I noticed the `.publish.attestation` files in the releases...

Author: dannyadair

.github/workflows/semantic-release.yaml

@@ -59,14 +59,6 @@ jobs:
           fi
           exit $status
 
-      # Wait for the outcome of
-      # https://github.com/pypa/gh-action-pypi-publish/issues/357
-      #- name: Sign the release with Sigstore
-      #  if: steps.release.outputs.released == 'true'
-      #  uses: sigstore/gh-action-sigstore-python@v3.0.0
-      #  with:
-      #    inputs: dist/*
-
       - name: Publish package distributions to PyPI
         if: steps.release.outputs.released == 'true'
         uses: pypa/gh-action-pypi-publish@release/v1