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/cmake.yml

@@ -21,7 +21,7 @@ jobs:
   build-gcc:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Build & Test
         uses: ashutoshvarma/action-cmake-build@master
         with:
@@ -37,7 +37,7 @@ jobs:
   build-clang:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Build & Test
         uses: ashutoshvarma/action-cmake-build@master
         with:

.github/workflows/go.yml

@@ -17,7 +17,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Go
         uses: actions/setup-go@v6
         with:

.github/workflows/gradle.yml

@@ -17,7 +17,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           lfs: true
       - name: Set up JDK 17

.github/workflows/markdown-link-check.yml

@@ -18,7 +18,7 @@ jobs:
   markdown-link-check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: gaurav-nelson/github-action-markdown-link-check@v1
         with:
           use-quiet-mode: 'yes'

.github/workflows/maven.yml

@@ -17,7 +17,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up JDK 17
         uses: actions/setup-java@v5
         with:

.github/workflows/npm.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with:

.github/workflows/pytest.yml

@@ -21,7 +21,7 @@ jobs:
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6
         with: