Bump redhat-plumbers-in-action/differential-shellcheck (#71)

Bumps [redhat-plumbers-in-action/differential-shellcheck](https://github.com/redhat-plumbers-in-action/differential-shellcheck) from 5.1.0 to 5.1.1.
- [Release notes](https://github.com/redhat-plumbers-in-action/differential-shellcheck/releases)
- [Changelog](https://github.com/redhat-plumbers-in-action/differential-shellcheck/blob/main/docs/CHANGELOG.md)
- [Commits](redhat-plumbers-in-action/differential-shellcheck@b9df2a9...c150708)

---
updated-dependencies:
- dependency-name: redhat-plumbers-in-action/differential-shellcheck
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/differential-shellcheck.yml

@@ -32,6 +32,6 @@ jobs:
 
       - id: ShellCheck
         name: Differential ShellCheck
-        uses: redhat-plumbers-in-action/differential-shellcheck@b9df2a9417f69c056e0aeaf870abd9a2065a403e # pin@aa647ec4466543e8555c2c3b648124a9813cee44
+        uses: redhat-plumbers-in-action/differential-shellcheck@c15070885a82a2c93db8a765d332c38c50dde8b3 # pin@aa647ec4466543e8555c2c3b648124a9813cee44
         with:
           token: ${{ secrets.GITHUB_TOKEN }}