Build(deps): Bump actions/checkout from 5 to 6 in the actions group (#1126)

Bumps the 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: actions
...

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

Author: dependabot[bot]

.github/workflows/ci-build.yml

@@ -78,7 +78,7 @@ jobs:
         python-version: ['3.10', '3.11', '3.12', '3.13']
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install the latest version of uv and set the python version
         uses: astral-sh/setup-uv@v7
@@ -107,7 +107,7 @@ jobs:
         extras-version: ['fluent-all', 'mapdl-all', 'tools']
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install the latest version of uv and set the python version
         uses: astral-sh/setup-uv@v7

.github/workflows/update-gh-pages.yml

@@ -28,7 +28,7 @@ jobs:
         python -m pip install requests
 
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Copy tools folder to /tmp and run sitemap script
       working-directory: /tmp
@@ -37,7 +37,7 @@ jobs:
         python ./tools/catsitemap.py
 
     - name: Checkout repository gh-pages branch
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: gh-pages