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/bot.yml

@@ -23,7 +23,7 @@ jobs:
             OUTPUTDIR: lnac-bot-win-x64
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v4
         with:

.github/workflows/client.yml

@@ -23,7 +23,7 @@ jobs:
             OUTPUTDIR: lnac-client-win-x64
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup .NET Core
         uses: actions/setup-dotnet@v4
         with:

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
       version: ${{ steps.version.outputs.version }}
       tag: ${{ steps.version.outputs.tag }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -81,7 +81,7 @@ jobs:
     name: Run tests
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-dotnet@v4
         with:
           dotnet-version: ${{ env.DOTNET_VERSION }}
@@ -141,7 +141,7 @@ jobs:
             artifact: lnac-bot-win-x64
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-dotnet@v4
         with:
           dotnet-version: ${{ env.DOTNET_VERSION }}

.github/workflows/server.yml

@@ -23,7 +23,7 @@ jobs:
                       OUTPUTDIR: lnac-server-win-x64
 
         steps:
-            - uses: actions/checkout@v4
+            - uses: actions/checkout@v6
             - name: Setup .NET Core
               uses: actions/setup-dotnet@v4
               with: