Bump zgosalvez/github-actions-ensure-sha-pinned-actions

Bumps [zgosalvez/github-actions-ensure-sha-pinned-actions](https://github.com/zgosalvez/github-actions-ensure-sha-pinned-actions) from 3.0.17 to 3.0.21.
- [Release notes](https://github.com/zgosalvez/github-actions-ensure-sha-pinned-actions/releases)
- [Commits](zgosalvez/github-actions-ensure-sha-pinned-actions@5d6ac37...6eb1abd)

---
updated-dependencies:
- dependency-name: zgosalvez/github-actions-ensure-sha-pinned-actions
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -32,7 +32,7 @@ jobs:
     - name: Ensure SHA pinned actions
       uses:
         # yamllint disable-line rule:line-length
-        zgosalvez/github-actions-ensure-sha-pinned-actions@5d6ac37a4cef8b8df67f482a8e384987766f0213  # v3.0.17
+        zgosalvez/github-actions-ensure-sha-pinned-actions@6eb1abde32fed00453b0d03497f4ba4fecba146d  # v3.0.21
   list-variants:
     name: List variants
     permissions: