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/build-sphinx.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
         ref: ${{ github.event.pull_request.head.sha }}

.github/workflows/pre-commit.yml

@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: recursive
 

.github/workflows/pypi-publish.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout source
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         submodules: recursive
         fetch-depth: 0

.github/workflows/test-sphinx.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
         ref: ${{ github.event.pull_request.head.sha }}

.github/workflows/update-branch-on-pr.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout repo
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       if: ${{ github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name && github.event.label.name == 'please test' }}
       with:
         ref: ${{ github.event.pull_request.head.sha }}