Bump actions/checkout from 5 to 6 in the all-actions group

Bumps the all-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: all-actions
...

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

Author: dependabot[bot]

.github/workflows/documentation.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: [ubuntu-latest]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Lint markdown files
         uses: nosborn/github-action-markdown-cli@v3

.github/workflows/php.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ['ubuntu-latest']
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -58,7 +58,7 @@ jobs:
       - name: Setup problem matchers for PHP
         run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -124,7 +124,7 @@ jobs:
       - name: Setup problem matchers for PHP
         run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -180,7 +180,7 @@ jobs:
           git config --global core.autocrlf false
           git config --global core.eol lf
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$GITHUB_ENV"
@@ -242,7 +242,7 @@ jobs:
           git config --global core.autocrlf false
           git config --global core.eol lf
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Get composer cache directory
         run: echo COMPOSER_CACHE="$(composer config cache-files-dir)" >> "$env:GITHUB_ENV"
@@ -265,7 +265,7 @@ jobs:
     runs-on: [ubuntu-latest]
     needs: [unit-tests-linux]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/download-artifact@v6
         with: