Update cpp.yml

Author: AtomicNibble

.github/workflows/cpp.yml

@@ -38,7 +38,7 @@ jobs:
       run: |
         ./build/release_x64/TDissUnitTester --gtest_output=xml:test_results.xml
     - name: Upload test results
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
         name: test-results
         path: test_results.xml