Update .NET version on GitHub Actions

Author: Maxhy

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'windows-latest']
-        dotnet-version: ['6.0.x' ]
+        dotnet-version: ['8.0.x' ]
 
     steps:
     - uses: actions/checkout@v3