Fix std::memory_order according to changes in C++20

The new code should be compatible with C++17 as well

Sofa/framework/Simulation/Core/src/sofa/simulation/DefaultTaskScheduler.cpp

@@ -224,7 +224,7 @@ void DefaultTaskScheduler::WaitForWorkersToBeReady()
 
 void DefaultTaskScheduler::setMainTaskStatus(const Task::Status* mainTaskStatus)
 {
-    m_mainTaskStatus.store(mainTaskStatus, std::memory_order::memory_order_relaxed);
+    m_mainTaskStatus.store(mainTaskStatus, std::memory_order_relaxed);
 }
 
 bool DefaultTaskScheduler::testMainTaskStatus(const Task::Status* status)