Bump actions/checkout from 5 to 6 (#13937)

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](https://github.com/actions/checkout/compare/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>

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - run: sudo apt-get update && sudo apt-get install -y libhdf5-dev
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
         with:
           enable-cache: true

.github/workflows/devcontainer_ci.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: devcontainers/ci@v0.3
         with:
           push: never

.github/workflows/directory_writer.yml

@@ -6,7 +6,7 @@ jobs:
   directory_writer:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - uses: actions/setup-python@v6

.github/workflows/project_euler.yml

@@ -21,7 +21,7 @@ jobs:
           libxml2-dev libxslt-dev
           libhdf5-dev
           libopenblas-dev
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
       - uses: actions/setup-python@v6
         with:
@@ -39,7 +39,7 @@ jobs:
           libxml2-dev libxslt-dev
           libhdf5-dev
           libopenblas-dev
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
       - uses: actions/setup-python@v6
         with:

.github/workflows/ruff.yml

@@ -11,6 +11,6 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
       - run: uvx ruff check --output-format=github .

.github/workflows/sphinx.yml

@@ -32,7 +32,7 @@ jobs:
           libxml2-dev libxslt-dev
           libhdf5-dev
           libopenblas-dev
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
       - uses: actions/setup-python@v6
         with: