Update actions/checkout action to v6 (#163)

Co-authored-by: horothesun-renovate[bot] <155104562+horothesun-renovate[bot]@users.noreply.github.com>

Author: horothesun-renovate[bot]

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Run ShellCheck
         uses: ludeeus/action-shellcheck@2.0.0

.github/workflows/ecr_cleanup.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v5