Bump actions/checkout from 5 to 6 (#928)

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

Author: dependabot[bot]

.github/workflows/release_documentation.yml

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

.github/workflows/release_packages.yml

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

.github/workflows/test.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
@@ -44,7 +44,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v5