chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/shellcheck.yml

@@ -12,6 +12,6 @@ jobs:
     name: ShellCheck
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
       - name: Run ShellCheck
         run: find . -type f -name "*.sh" -exec shellcheck {} +