Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout Code
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
       - name: Install Dependencies
         uses: NullVoxPopuli/action-setup-pnpm@v2
       - name: Lint JS

.github/workflows/staging-cleanup.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout Code
-        uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6
       - name: Install Dependencies
         uses: NullVoxPopuli/action-setup-pnpm@v2
       - name: Delete staging site