Update publish-nuget.yml

Author: marcin-golebiowski

.github/workflows/publish-nuget.yml

@@ -17,7 +17,7 @@ jobs:
     - name: Setup dotnet tooling
       uses: actions/setup-dotnet@master
       with:
-        dotnet-version: '5.0.100'
+        dotnet-version: '6.0.x'
 
     - name: Restore dependencies
       run: