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/cmake-build-ci.yml

@@ -47,7 +47,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Prepare environment (for cur gnu on ubuntu-24.04)
         if: (env.OS_VER=='ubuntu-24.04') && (env.CC_VND=='gnu') && (env.CC_VER=='cur')
         run: |
@@ -139,8 +139,8 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v5
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6
         with:
           repository: memcached/memcached
           path: memcached
@@ -229,7 +229,7 @@ jobs:
       contents: read
     continue-on-error: true
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Install dependencies (macOS)
@@ -303,7 +303,7 @@ jobs:
       CC_VND: ${{ matrix.cc_vnd }}
       CC_VER: ${{ matrix.cc_ver }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Prepare environment (Windows)
@@ -383,7 +383,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Prepare environment (for new gnu on ubuntu-22.04)

.github/workflows/docs-publish-pages.yml

@@ -20,7 +20,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install dependencies
         run: |
           sudo apt-get update -y