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/code-transformations.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         ref: ${{ github.event.pull_request.head.sha }}
         persist-credentials: false

.github/workflows/datamodel-doc.yml

@@ -10,20 +10,20 @@ jobs:
     steps:
 
       - name: Checkout O2
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: O2
           persist-credentials: false
 
       - name: Checkout O2Physics
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: AliceO2Group/O2Physics
           path: O2Physics
           persist-credentials: false
 
       - name: Checkout documentation
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: AliceO2Group/analysis-framework
           path: analysis-framework

.github/workflows/doxygen.yml

@@ -13,7 +13,7 @@ jobs:
       run: |
         sudo apt-get update -y
         sudo apt-get install -y doxygen doxygen-doc doxygen-latex doxygen-gui graphviz cmake
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         ref: "dev"
         persist-credentials: false

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
         branch=$(echo ${{ github.event.inputs.tag }}-patches | tr . - | sed -e's/-[0-9]*-patches$/-patches/')
         EOF
       id: decide_release_branch
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         ref: "dev"
     - name: Tag branch (or create one before tagging if does not exists)

.github/workflows/reports.yml

@@ -17,7 +17,7 @@ jobs:
     if: github.repository == 'AliceO2Group/AliceO2'
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python 3.10
       uses: actions/setup-python@v6
       with: