ci(deps): bump actions/checkout from 5.0.1 to 6.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.1 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5.0.1...v6.0.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ jobs:
   actionlint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5.0.1
+      - uses: actions/checkout@v6.0.0
 
       - name: Check workflow files
         uses: docker://rhysd/actionlint:1.7.8
@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v5.0.1
+        uses: actions/checkout@v6.0.0
 
       - name: Setup Node 🔧
         uses: actions/setup-node@v6
@@ -46,7 +46,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v5.0.1
+        uses: actions/checkout@v6.0.0
 
       - name: Setup Node 🔧
         uses: actions/setup-node@v6
@@ -64,7 +64,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v5.0.1
+        uses: actions/checkout@v6.0.0
 
       - name: Setup Node 🔧
         uses: actions/setup-node@v6
@@ -82,7 +82,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v5.0.1
+        uses: actions/checkout@v6.0.0
 
       - name: Test script
         run: scripts/detect-broken-links.sh