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/deploy.yml

@@ -23,7 +23,7 @@ jobs:
       CIBW_ARCHS_LINUX: "x86_64 i686 aarch64"
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: "recursive"
           fetch-depth: 0
@@ -51,7 +51,7 @@ jobs:
         cibw_archs: ["arm64"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: "recursive"
           fetch-depth: 0
@@ -93,7 +93,7 @@ jobs:
     name: Build source distribution
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: "recursive"
           fetch-depth: 0

.github/workflows/run-tests.yml

@@ -18,7 +18,7 @@ jobs:
         python-version: [3.8, 3.9, "3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: "recursive"
       - name: Set up Python ${{ matrix.python-version }}