Update release.yml

Author: rickbutterfield

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
     - name: Setup .NET
       uses: actions/setup-dotnet@v2
       with:
-        dotnet-version: 6.0.x
+        dotnet-version: 8.0.x
 
     - name: Build project
       run: dotnet build src\Umbraco.Community.Sustainability\Umbraco.Community.Sustainability.csproj --configuration Release