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/build_and_test.yml

@@ -32,7 +32,7 @@ jobs:
           - { os: windows-latest, compiler: msvc, cxx_stdlib: msvc }
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Prepare dependencies
       run: |
          if [ "$RUNNER_OS" == "Linux" ]; then

.github/workflows/build_bazel.yml

@@ -26,7 +26,7 @@ jobs:
             # ubuntu-18.04 & mac-os do not work due to compile error on asio
             # windows-2019 not included to spare free minutes
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Prepare dependencies
       run: |
          if [ "$RUNNER_OS" == "Linux" ]; then

.github/workflows/codeql.yml

@@ -58,7 +58,7 @@ jobs:
         # your codebase is analyzed, see https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/codeql-code-scanning-for-compiled-languages
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Install dependencies
     - name: Prepare dependencies

.github/workflows/doxygen-gh-pages.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout 🛎️
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Prepare dependencies
         run: sudo apt-get update && sudo apt-get -yq install libasio-dev doxygen mkdocs graphviz zlib1g-dev gcc clang make cmake python3 python3-pip git openssl libssl-dev
       - name: prepate pip dependencies