Merge pull request #371 from OpenPrinting/dependabot/github_actions/redhat-plumbers-in-action/differential-shellcheck-5.4.0

Bump redhat-plumbers-in-action/differential-shellcheck from 5.3.0 to 5.4.0

Author: zdohnal

.github/workflows/differential-shellcheck.yml

@@ -21,6 +21,6 @@ jobs:
           fetch-depth: 0
 
       - name: Differential ShellCheck
-        uses: redhat-plumbers-in-action/differential-shellcheck@60c9f2b924a9c5a2ddbb25e7b23e8e11b56faab9
+        uses: redhat-plumbers-in-action/differential-shellcheck@cc6721c45a8800cc666de45493545a07a638d121
         with:
           token: ${{ secrets.GITHUB_TOKEN }}