Bump SDK to .NET 8

Author: khellang

.github/workflows/build.yml

@@ -23,10 +23,10 @@ jobs:
         with:
           dotnet-version: "3.1.x"
 
-      - name: Setup .NET 6 SDK
+      - name: Setup .NET 8 SDK
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: "6.0.x"
+          dotnet-version: "8.0.x"
 
       - name: Test
         run: dotnet test --collect:"XPlat Code Coverage"