Bump actions/checkout from 5 to 6 (#1225)

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

Author: dependabot[bot]

.github/workflows/cd_docs.yml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Python
         uses: actions/setup-python@v6

.github/workflows/cd_release.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Set up git user
       run: |
@@ -124,7 +124,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # This step is necessary because while this is done in the job above,
     # this job runs with the original commit SHA and does not have this change.
@@ -188,7 +188,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # This step is necessary because while this is done in the job above,
     # this job runs with the original commit SHA and does not have this change.

.github/workflows/ci_build_wheels.yml

@@ -75,7 +75,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Python for running cibuildwheel
         uses: actions/setup-python@v6

.github/workflows/ci_tests.yml

@@ -85,7 +85,7 @@ jobs:
             cppcheck:p
 
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6

.github/workflows/container_builds_weekly.yml

@@ -77,7 +77,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Docker buildx
         uses: docker/setup-buildx-action@v3

.github/workflows/static_analysis.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Update submodules
       run: |