Bump actions/checkout from 6 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -27,7 +27,7 @@ jobs:
           valgrind
         env:
           DEBIAN_FRONTEND: noninteractive
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - run: mkdir -p build
       - run: >
           cmake ..
@@ -70,5 +70,5 @@ jobs:
   yamllint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - run: yamllint .

.github/workflows/python.yaml

@@ -14,7 +14,7 @@ jobs:
   sdist:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - run: python -m pip install -U build
       - run: python -m build --sdist
       - uses: actions/upload-artifact@v7
@@ -31,7 +31,7 @@ jobs:
             arch: aarch64
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: pypa/cibuildwheel@v3.4.1
       - uses: actions/upload-artifact@v7
         with: