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] <support@github.com>

Author: dependabot[bot]

.github/workflows/build_docs.yml

@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install dependencies for pyvista
         run: apt-get update && apt-get install -y libxrender1

.github/workflows/deploy_docs.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Pages
         uses: actions/configure-pages@v5

.github/workflows/docker-image.yml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Log in to the Container registry
         uses: docker/login-action@v3

.github/workflows/pre-commit.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       # This action sets the current path to the root of your github repo
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install pre-commit
         run: python3 -m pip install pre-commit

.github/workflows/pypi.yml

@@ -15,7 +15,7 @@ jobs:
   dist:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Build SDist and wheel
       run: pipx run build

.github/workflows/test_package_coverage.yml

@@ -23,7 +23,7 @@ jobs:
         ]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install package
         run: |