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: astral-sh/setup-uv@v7
@@ -28,13 +28,13 @@ jobs:
         name: Typos
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   uses: crate-ci/typos@master
 
     basedpyright:
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 EXTRA_INSTALL="pytest types-colorama types-Pygments scipy-stubs"
@@ -54,7 +54,7 @@ jobs:
           matrix:
             os: [ubuntu-latest, macos-latest]
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/build-and-test-py-project-within-miniconda.sh
@@ -64,7 +64,7 @@ jobs:
         name: Conda Pytest with Intel CL
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 curl -L -O https://raw.githubusercontent.com/illinois-scicomp/machine-shop-maintenance/main/install-intel-icd.sh
@@ -83,7 +83,7 @@ jobs:
         name: Conda Pytest without arg check
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/build-and-test-py-project-within-miniconda.sh
@@ -94,7 +94,7 @@ jobs:
         name: Conda Pytest Twice (for cache behavior)
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 # This test makes sure that loopy can run with kernels loaded from disk cache.
@@ -112,7 +112,7 @@ jobs:
         name: Conda Examples
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             run: |
                 curl -L -O https://tiker.net/ci-support-v0
@@ -130,7 +130,7 @@ jobs:
         name: Documentation
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -
             uses: actions/setup-python@v6
             with:
@@ -150,7 +150,7 @@ jobs:
         name: Tests for downstream project ${{ matrix.downstream_project }}
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v5
+        -   uses: actions/checkout@v6
         -   name: "Main Script"
             env:
                 DOWNSTREAM_PROJECT: ${{ matrix.downstream_project }}
@@ -200,7 +200,7 @@ jobs:
             name: Validate CITATION.cff
             runs-on: ubuntu-latest
             steps:
-            -   uses: actions/checkout@v5
+            -   uses: actions/checkout@v6
             -   uses: actions/setup-python@v6
             -   run: |
                     pip install cffconvert