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] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         python-version: ["3.10", "3.11", "3.12"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install uv
         uses: astral-sh/setup-uv@v7
         with:
@@ -53,7 +53,7 @@ jobs:
     needs: build
     if: github.event.pull_request
     steps:
-        - uses: actions/checkout@v5
+        - uses: actions/checkout@v6
         - name: download covearge
           uses: actions/download-artifact@v6
           with:

.github/workflows/docstrings.yml

@@ -12,7 +12,7 @@ jobs:
   docstrings:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: chartboost/ruff-action@v1
         with:
             args: check --select="D"

.github/workflows/isort.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: isort/isort-action@v1
         with:
             sortPaths: "src" # only sort files in the src directory

.github/workflows/lint.yml

@@ -12,10 +12,10 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: chartboost/ruff-action@v1
   black:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: psf/black@stable

.github/workflows/release.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Install uv
       uses: astral-sh/setup-uv@v7
       with: