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.yml

@@ -37,7 +37,7 @@ jobs:
           - runner: ubuntu-22.04
             target: ppc64le
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actions/setup-python@v6
         with:
           python-version: "3.8"
@@ -68,7 +68,7 @@ jobs:
           - runner: ubuntu-22.04
             target: armv7
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actions/setup-python@v6
         with:
           python-version: "3.8"
@@ -100,7 +100,7 @@ jobs:
             target: aarch64
             python_arch: arm64
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actions/setup-python@v6
         with:
           python-version: "3.13"
@@ -127,7 +127,7 @@ jobs:
           - runner: macos-latest
             target: aarch64
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - uses: actions/setup-python@v6
         with:
           python-version: "3.8"
@@ -146,7 +146,7 @@ jobs:
   sdist:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
       - name: Build sdist
         uses: PyO3/maturin-action@v1
         with: