Bump actions/checkout from 5 to 6 (#41)

* 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>

* Add permissions for documentation job in CI

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Pere Mato <peremato@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/Downgrade.yml

@@ -15,7 +15,7 @@ jobs:
       matrix:
         version: ['lts']
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}

.github/workflows/ci.yaml

@@ -23,9 +23,9 @@ jobs:
           - x64
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Checkout G4Examples
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: JuliaHEP/G4Examples.jl
           path: examples
@@ -47,11 +47,13 @@ jobs:
   docs:
     name: Documentation
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Checkout G4Examples
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: JuliaHEP/G4Examples.jl
           path: examples