update workflow

Author: jonghough

.github/workflows/unit-test.yaml

@@ -21,7 +21,7 @@ jobs:
       - name: Unit test
         run: dotnet test SharpGraph.sln --logger trx --results-directory "TestResults-${{ matrix.dotnet-version }}"
       - name: Upload dotnet test results
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: dotnet-results-${{ matrix.dotnet-version }}
           path: TestResults-${{ matrix.dotnet-version }}