build(deps): bump sigstore/sigstore-conformance in the actions group (#1599)

Bumps the actions group with 1 update: [sigstore/sigstore-conformance](https://github.com/sigstore/sigstore-conformance).


Updates `sigstore/sigstore-conformance` from 0.0.21 to 0.0.22
- [Release notes](https://github.com/sigstore/sigstore-conformance/releases)
- [Commits](sigstore/sigstore-conformance@244638a...250df5a)

---
updated-dependencies:
- dependency-name: sigstore/sigstore-conformance
  dependency-version: 0.0.22
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/conformance.yml

@@ -26,7 +26,7 @@ jobs:
       - name: install sigstore-python
         run: python -m pip install .
 
-      - uses: sigstore/sigstore-conformance@244638a7a138ae9f6106cfe2d44a698eccd3bef7 # v0.0.21
+      - uses: sigstore/sigstore-conformance@250df5acf1186936375a80d7258c51602bd0b8f3 # v0.0.22
         with:
           entrypoint: ${{ github.workspace }}/test/integration/sigstore-python-conformance
           xfail: "test_verify*intoto-with-custom-trust-root]" # see issue 1442