Bump actions/checkout from 4 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: astral-sh/setup-uv@v6
         with:
           enable-cache: true

.github/workflows/devcontainer_ci.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: devcontainers/[email protected]
         with:
           push: never

.github/workflows/directory_writer.yml

@@ -6,7 +6,7 @@ jobs:
   directory_writer:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
         with:
           fetch-depth: 0
       - uses: actions/setup-python@v5

.github/workflows/project_euler.yml

@@ -14,7 +14,7 @@ jobs:
   project-euler:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: astral-sh/setup-uv@v6
       - uses: actions/setup-python@v5
         with:
@@ -24,7 +24,7 @@ jobs:
   validate-solutions:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: astral-sh/setup-uv@v6
       - uses: actions/setup-python@v5
         with:

.github/workflows/ruff.yml

@@ -11,6 +11,6 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: astral-sh/setup-uv@v6
       - run: uvx ruff check --output-format=github .

.github/workflows/sphinx.yml

@@ -25,7 +25,7 @@ jobs:
   build_docs:
     runs-on: ubuntu-24.04-arm
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: astral-sh/setup-uv@v6
       - uses: actions/setup-python@v5
         with: