Bump actions/checkout from 5 to 6 (#181)

Author: dependabot[bot]

.github/workflows/CI.yml

@@ -13,7 +13,7 @@ jobs:
   build:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Setup .NET
       uses: actions/setup-dotnet@v5

.github/workflows/Release.yml

@@ -11,7 +11,7 @@ jobs:
   build:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0