⬆️ Bump actions/checkout from 4 to 6 (#1067)

⬆️ Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/test-formats.yml

@@ -18,7 +18,7 @@ jobs:
         format: ["man", "text"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:
@@ -42,7 +42,7 @@ jobs:
         format: ["latex"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:
@@ -41,7 +41,7 @@ jobs:
     name: "pytest: py${{ matrix.python-version }}, sphinx${{ matrix.sphinx }}, on ${{ matrix.os }}"
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -78,7 +78,7 @@ jobs:
 
     steps:
     - name: Checkout source
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:
@@ -133,7 +133,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout source
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with:
@@ -156,7 +156,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout source
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v6
       with: