Bump actions/checkout from 5.0.0 to 6.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5.0.0...v6.0.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/pythonpackage.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout sources
-      uses: actions/checkout@v5.0.0
+      uses: actions/checkout@v6.0.0
     - name: Set up Python
       uses: actions/setup-python@v6.0.0
       with:
@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout sources
-      uses: actions/checkout@v5.0.0
+      uses: actions/checkout@v6.0.0
     - name: Set up Python
       uses: actions/setup-python@v6.0.0
       with:
@@ -47,7 +47,7 @@ jobs:
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
     - name: Checkout sources
-      uses: actions/checkout@v5.0.0
+      uses: actions/checkout@v6.0.0
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6.0.0
       with:
@@ -74,7 +74,7 @@ jobs:
     needs: test
     steps:
     - name: Checkout sources
-      uses: actions/checkout@v5.0.0
+      uses: actions/checkout@v6.0.0
     - name: Set up Python
       uses: actions/setup-python@v6.0.0
       with:

.github/workflows/pythonpublish.yml

@@ -8,7 +8,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5.0.0
+    - uses: actions/checkout@v6.0.0
     - name: Set up Python
       uses: actions/setup-python@v6.0.0
       with: