updated actions/upload-artifact to v4 as build breaks as v3 is deprecated

Author: David Turvey

.github/workflows/build.yml

@@ -35,7 +35,7 @@ jobs:
     - name: Test
       run: dotnet test --no-build --verbosity normal --logger trx --results-directory "TestResults"
     - name: Upload test results
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: dotnet-results
         path: TestResults