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] <support@github.com>

Author: dependabot[bot]

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Install Python 3.x
       uses: actions/setup-python@v6
       with:
@@ -42,7 +42,7 @@ jobs:
           - macOS-latest
     steps:
     - name: Check out repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Install Python 3.x
       uses: actions/setup-python@v6
       with:

.github/workflows/tests.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Install Python 3.x
       uses: actions/setup-python@v6
       with:
@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Install Python 3.x
       uses: actions/setup-python@v6
       with:
@@ -70,7 +70,7 @@ jobs:
             is_main: false
     steps:
     - name: Check out repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Install Python ${{ matrix.python }}
       uses: actions/setup-python@v6
       with: