chore: 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/codeql.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3

.github/workflows/e2e.yml

@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up Python
         uses: actions/setup-python@v5

.github/workflows/integration.yml

@@ -14,7 +14,7 @@ jobs:
       version: ${{ steps.version.outputs.VERSION }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up Python
         uses: actions/setup-python@v5
@@ -61,7 +61,7 @@ jobs:
     continue-on-error: ${{ matrix.python-version == '3.15-dev' }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
@@ -112,7 +112,7 @@ jobs:
       image: ${{ matrix.distro }}:${{ matrix.version }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Download packages
         uses: actions/download-artifact@v4
@@ -169,7 +169,7 @@ jobs:
       image: ${{ matrix.image }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Download packages
         uses: actions/download-artifact@v4
@@ -224,7 +224,7 @@ jobs:
       image: ${{ matrix.image || format('{0}:{1}', matrix.distro, matrix.version) }}
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install pip and dependencies (Debian/Ubuntu)
         if: matrix.distro != ''

.github/workflows/pypi.yml

@@ -23,7 +23,7 @@ jobs:
       id-token: write
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.inputs.ref || github.ref }}
 

.github/workflows/release.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.inputs.ref || github.ref }}
 
@@ -122,7 +122,7 @@ jobs:
           echo "${{ secrets.GPG_PRIVATE_KEY }}" | base64 -d | gpg --batch --import
 
       - name: Checkout gh-pages branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: gh-pages
           path: gh-pages

.github/workflows/validate.yml

@@ -16,7 +16,7 @@ jobs:
     continue-on-error: ${{ matrix.python-version == '3.15-dev' }}
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5