Remove netcoreapp31 from GitHub Actions build

Author: StefH

.github/workflows/ci.yml

@@ -33,11 +33,6 @@ jobs:
       run: |
         dotnet build ./test/System.Linq.Dynamic.Core.Tests.Net6/System.Linq.Dynamic.Core.Tests.Net6.csproj -c Release -p:buildType=azure-pipelines-ci
         dotnet test ./test/System.Linq.Dynamic.Core.Tests.Net6/System.Linq.Dynamic.Core.Tests.Net6.csproj -c Release -p:buildType=azure-pipelines-ci --no-build
-
-    - name: Run Tests netcoreapp31
-      run: |
-        dotnet build ./test/System.Linq.Dynamic.Core.Tests/System.Linq.Dynamic.Core.Tests.csproj -c Release -f netcoreapp31 -p:buildType=azure-pipelines-ci
-        dotnet test ./test/System.Linq.Dynamic.Core.Tests/System.Linq.Dynamic.Core.Tests.csproj -c Release -f netcoreapp31 -p:buildType=azure-pipelines-ci --no-build
     
     - name: Run Tests net452
       run: |