Update dotnet.yml

Author: danielgerlag

.github/workflows/dotnet.yml

@@ -17,6 +17,7 @@ jobs:
         dotnet-version: | 
           3.1.x
           6.0.x
+          8.0.x
     - name: Restore dependencies
       run: dotnet restore
     - name: Build
@@ -134,4 +135,4 @@ jobs:
       - name: Build
         run: dotnet build --no-restore
       - name: Elasticsearch Tests
-        run: dotnet test test/WorkflowCore.Tests.Elasticsearch --no-build --verbosity normal -p:ParallelizeTestCollections=false
+        run: dotnet test test/WorkflowCore.Tests.Elasticsearch --no-build --verbosity normal -p:ParallelizeTestCollections=false