chore: attestations (#1916)

.github/workflows/release.yml

@@ -28,9 +28,12 @@ jobs:
     needs: [dist]
     runs-on: ubuntu-latest
     if: github.event_name == 'release' && github.event.action == 'published'
-    environment: pypi
+    environment:
+      name: pypi
+      url: https://pypi.org/p/cibuildwheel
     permissions:
       id-token: write
+      attestations: write
 
     steps:
     - uses: actions/download-artifact@v4
@@ -39,4 +42,9 @@ jobs:
         path: dist
         merge-multiple: true
 
+    - name: Generate artifact attestation for sdist and wheel
+      uses: actions/attest-build-provenance@173725a1209d09b31f9d30a3890cf2757ebbff0d # v1.1.2
+      with:
+        subject-path: "dist/cibuildwheel-*"
+
     - uses: pypa/gh-action-pypi-publish@release/v1