Bump actions/checkout from 5 to 6 in the github-actions group (#3360)

Bumps the github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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](https://github.com/actions/checkout/compare/v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/macos_build.yml

@@ -17,7 +17,7 @@ jobs:
           - "3.13"
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       # Normally, we would use the superbly maintained...
       # - uses: actions/setup-python@v2
       #   with:

.github/workflows/modified_scripts_build.yml

@@ -7,7 +7,7 @@ jobs:
       versions: ${{steps.modified-versions.outputs.versions}}
       versions_cpython_only: ${{steps.modified-versions.outputs.versions_cpython_only}}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: git fetch origin "$GITHUB_BASE_REF"
       - shell: bash
         run: >
@@ -40,7 +40,7 @@ jobs:
         os: ["macos-14", "macos-15", "macos-15-intel"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           #envvars
           export PYENV_ROOT="$GITHUB_WORKSPACE"
@@ -101,7 +101,7 @@ jobs:
         os: ["macos-14", "macos-15", "macos-15-intel"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           #envvars
           export PYENV_ROOT="$GITHUB_WORKSPACE"
@@ -163,7 +163,7 @@ jobs:
         os: ["ubuntu-22.04", "ubuntu-24.04"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           #envvars
           export PYENV_ROOT="$GITHUB_WORKSPACE"
@@ -222,7 +222,7 @@ jobs:
         os: ["ubuntu-latest"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           #envvars
           export PYENV_ROOT="$GITHUB_WORKSPACE"

.github/workflows/pyenv_tests.yml

@@ -16,7 +16,7 @@ jobs:
           - macos-14
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       # Normally, we would use the superbly maintained...
       # - uses: actions/setup-python@v2
       #   with:

.github/workflows/ubuntu_build.yml

@@ -17,7 +17,7 @@ jobs:
           - "3.13"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       # Normally, we would use the superbly maintained...
       # - uses: actions/setup-python@v2
       #   with: