build(deps): bump redhat-plumbers-in-action/differential-shellcheck

Bumps [redhat-plumbers-in-action/differential-shellcheck](https://github.com/redhat-plumbers-in-action/differential-shellcheck) from 5.5.5 to 5.5.6.
- [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@0d9e5b2...d965e66)

---
updated-dependencies:
- dependency-name: redhat-plumbers-in-action/differential-shellcheck
  dependency-version: 5.5.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

.github/workflows/differential-shellcheck.yml

@@ -32,6 +32,6 @@ jobs:
 
       - id: ShellCheck
         name: Differential ShellCheck
-        uses: redhat-plumbers-in-action/differential-shellcheck@0d9e5b29625f871e6a4215380486d6f1a7cb6cdd # pin@aa647ec4466543e8555c2c3b648124a9813cee44
+        uses: redhat-plumbers-in-action/differential-shellcheck@d965e66ec0b3b2f821f75c8eff9b12442d9a7d1e # pin@aa647ec4466543e8555c2c3b648124a9813cee44
         with:
           token: ${{ secrets.GITHUB_TOKEN }}