dep: Update actions/checkout action to v4 (#214)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/workflows/CI.yaml

@@ -15,7 +15,7 @@ jobs:
           dotnet-version: 6.0.x
 
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Run dotnet format check
         run: dotnet format -v diag --verify-no-changes
@@ -31,7 +31,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v3
@@ -47,7 +47,7 @@ jobs:
     runs-on: windows-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v3
@@ -75,7 +75,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v3