Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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/format-check.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Setup .NET
       uses: actions/setup-dotnet@v4

.github/workflows/publish.yml

@@ -11,7 +11,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:
@@ -33,7 +33,7 @@ jobs:
     permissions:
       contents: read
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup .NET
       uses: actions/setup-dotnet@v4
       with:

.github/workflows/update-readme.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         token: ${{ secrets.GITHUB_TOKEN }}