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] <support@github.com>

Author: dependabot[bot]

.github/workflows/codespell.yml

@@ -10,5 +10,5 @@ jobs:
   codespell:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: codespell-project/actions-codespell@v2

.github/workflows/config_options.yml

@@ -37,7 +37,7 @@ jobs:
       run:
         shell: bash -l {0}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Output g++ version . . .
         run: g++ --version
       - name: Install micromamba environment from environment.yml . . .
@@ -97,7 +97,7 @@ jobs:
             without-intrinsics: ""
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Output g++ version . . .
         run: g++ --version
       - name: Install GAP and clone/compile necessary packages . . .

.github/workflows/lint.yml

@@ -29,7 +29,7 @@ jobs:
           - cpplint
     steps:
       - name: Check out the repository . . .
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set up Python . . .
         uses: actions/setup-python@v6
       - name: Install ${{ matrix.linter }} with pip . . .

.github/workflows/manual.yml

@@ -22,7 +22,7 @@ jobs:
     name: compile and upload manual
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install TeX Live . . .
         run: |
           packages=(

.github/workflows/os.yml

@@ -40,7 +40,7 @@ jobs:
 
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: gap-actions/setup-cygwin@v2
         if: ${{ runner.os == 'Windows' }}
       - name: Output g++ version . . .

.github/workflows/release.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: gap-actions/setup-gap@v3
         with:
           gap-version: latest

.github/workflows/ubuntu.yml

@@ -47,7 +47,7 @@ jobs:
             pkgs-to-build: io* orb* datastructures* profiling* grape*
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Output g++ version . . .
         run: g++ --version
       - name: "Install GAP . . ."
@@ -67,7 +67,7 @@ jobs:
           cd ${GAPROOT}/pkg
           ../bin/BuildPackages.sh --strict ${{ matrix.pkgs-to-build }}
       - name: "Install digraphs-lib . . ."
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: digraphs/digraphs-lib
           path: digraphs-lib

.github/workflows/valgrind.yml

@@ -27,7 +27,7 @@ jobs:
     name: Ubuntu / GAP stable-4.15 / valgrind
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: "Output g++ version . . ."
         run: g++ --version
       - name: "Install Valgrind . . ."