Bump to .net 6.0

Author: rxtur

.github/workflows/demo.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: '5.0.x'
+        dotnet-version: '6.0.x'
 
     - name: Publish Blogifier
       run: dotnet publish -c Release -o release --nologo