ci(deps): bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/copilot-setup-steps.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       # Engines: Node >=20, npm >=10
       - name: Set up Node 20

.github/workflows/e2e.yml

@@ -37,7 +37,7 @@ jobs:
 
     steps:
       - name: 📥 Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: 🔧 Setup Node.js
         uses: actions/setup-node@v4

.github/workflows/label-issues.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Label issues and PRs
         uses: actions/labeler@v6

.github/workflows/lint-docs.yml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6
@@ -41,7 +41,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Check links in Markdown files
         uses: gaurav-nelson/github-action-markdown-link-check@v1