build(deps): 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/autopush.yml

@@ -10,7 +10,7 @@ jobs:
         if: startsWith(github.repository, 'inducer/')
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   run: |
                 curl -L -O https://tiker.net/ci-support-v0
                 . ./ci-support-v0

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
         name: Ruff
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
             with:
                 submodules: true
         -   uses: actions/setup-python@v6
@@ -32,7 +32,7 @@ jobs:
             matrix:
                 python-version: ['3.10', '3.12', '3.x']
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -
             uses: actions/setup-python@v6
             with:
@@ -49,7 +49,7 @@ jobs:
         name: Pytest on macOS
         runs-on: macos-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -
             uses: actions/setup-python@v6
             with:
@@ -67,7 +67,7 @@ jobs:
         name: Documentation
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -
             uses: actions/setup-python@v6
             with:

.github/workflows/wheels.yml

@@ -16,7 +16,7 @@ jobs:
     name: Build source distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           submodules: true
 
@@ -38,7 +38,7 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Build wheels
         uses: pypa/[email protected]
@@ -59,7 +59,7 @@ jobs:
     name: Deploy
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v')
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: download artifacts
         uses: actions/download-artifact@v6
         with: