chore(ci)(deps): bump actions/checkout from 4 to 6 (#13)

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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/assets.yml

@@ -20,7 +20,7 @@ jobs:
     name: Verify minified assets are up to date
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: '20'

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     name: PHPStan (PHP 8.1)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: shivammathur/setup-php@v2
         with:
           php-version: '8.1'
@@ -43,7 +43,7 @@ jobs:
     # required check once the team is comfortable acting on every advisory.
     continue-on-error: true
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: shivammathur/setup-php@v2
         with:
           php-version: '8.1'
@@ -60,7 +60,7 @@ jobs:
       matrix:
         php: ['8.1', '8.2', '8.3', '8.4']
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
@@ -86,7 +86,7 @@ jobs:
     runs-on: ubuntu-latest
     continue-on-error: true
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: shivammathur/setup-php@v2
         with:
           php-version: '8.1'

.github/workflows/codeql.yml

@@ -33,7 +33,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4