chore(deps): update actions/checkout action to v7

Author: renovate[bot]

.github/workflows/validation.yml

@@ -16,7 +16,7 @@ jobs:
     name: 'MarkdownLint'
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
       - name: Validate Markdown Sources
         uses: nosborn/github-action-markdown-cli@v3.3.0
         with:
@@ -26,7 +26,7 @@ jobs:
     name: 'ESLint'
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
       - name: Use Node.js ${{ env.node-version }}
         uses: actions/setup-node@v4
         with:
@@ -41,7 +41,7 @@ jobs:
     name: 'Stylelint'
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
       - name: Use Node.js ${{ env.node-version }}
         uses: actions/setup-node@v4
         with:
@@ -54,7 +54,7 @@ jobs:
   package-lock-is-up-to-date:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v7
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ env.node-version }}