Modify build workflow for .net upgrade

Author: gbakeman

.github/workflows/build-validate.yaml

@@ -13,7 +13,7 @@ on:
     - '**.vbproj'
 
 env:
-  DOTNET_VERSION: '4.7.2' # The .NET SDK version to use
+  DOTNET_VERSION: '4.8' # The .NET SDK version to use
   SLN_FILE: WinNUT_V2.sln
   DEBUG_OUTPUT: WinNUT_V2/WinNUT-Client/bin/Debug
 
@@ -38,9 +38,7 @@ jobs:
 
     # msbuild cannot handle .vdproj Installer projects, so only build debug for now.
     - name: Build solution
-      run: |
-        Write-Output "::echo::on"
-        msbuild.exe $env:SLN_FILE -p:Configuration=Debug
+      run: msbuild $env:SLN_FILE -p:Configuration=Debug
 
     # For now, let msbuild continue autogenerating assembly versions and base everything off of that.
     - name: Get AssemblyVersion generated by msbuild