chore(deps): pin actions/checkout action to 08c6903 (gemini-cli-extensions#42)

Co-authored-by: Averi Kitsch <akitsch@google.com>

Author: renovate-bot

.github/workflows/header-check.yml

@@ -24,7 +24,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: 'Checkout Repository'
-        uses: actions/checkout@v5
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5
 
       - name: Check License Header
         uses: apache/skywalking-eyes/header@main