Bump actions/checkout from 5 to 6 (#2317)

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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build-dev.yml

@@ -26,7 +26,7 @@ jobs:
     steps:
       -
         name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       -  
         name: Setup .NET
         uses: actions/setup-dotnet@v5

.github/workflows/pull-request-docs.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       -  
         name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       -  
         name: Build docs
         run: |

.github/workflows/pull-request.yml

@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
@@ -56,7 +56,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with: