Bump step-security/harden-runner from 2.9.0 to 2.9.1 (#976)

Bumps [step-security/harden-runner](https://github.com/step-security/harden-runner) from 2.9.0 to 2.9.1.
- [Release notes](https://github.com/step-security/harden-runner/releases)
- [Commits](step-security/harden-runner@0d38121...5c7944e)

---
updated-dependencies:
- dependency-name: step-security/harden-runner
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/cacert-publish.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: Harden Runner
-        uses: step-security/harden-runner@0d381219ddf674d61a7572ddd19d7941e271515c # v2.9.0
+        uses: step-security/harden-runner@5c7944e73c4c2a096b17a9cb74d65b6c2bbafbde # v2.9.1
         with:
           disable-sudo: true
           egress-policy: block