Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/php-cs-fixer.yml

@@ -14,7 +14,7 @@ jobs:
           php-version: 7.4
 
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get composer cache directory
         id: composer-cache

.github/workflows/phpmd.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get composer cache directory
         id: composer-cache

.github/workflows/phpstan.yml

@@ -13,7 +13,7 @@ jobs:
         with:
           php-version: 7.4
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         id: composer-cache

.github/workflows/phpunit.yml

@@ -19,7 +19,7 @@ jobs:
         env:
           COMPOSER_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         id: composer-cache

.github/workflows/rector.yml

@@ -14,7 +14,7 @@ jobs:
           php-version: 8.1
 
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get composer cache directory
         id: composer-cache