Update libqmatrixclient.

Enable member lazy loading.
Some Qt 5.12 fix.

src/userlistmodel.cpp

@@ -34,12 +34,8 @@ void UserListModel::setRoom(QMatrixClient::Room* room) {
     connect(m_currentRoom, &Room::memberRenamed, this,
             &UserListModel::userAdded);
     {
-      QElapsedTimer et;
-      et.start();
       m_users = m_currentRoom->users();
       std::sort(m_users.begin(), m_users.end(), room->memberSorter());
-      qDebug() << "Sorting" << m_users.size() << "user(s) in"
-               << m_currentRoom->displayName() << "took" << et;
     }
     for (User* user : m_users) {
       connect(user, &User::avatarChanged, this, &UserListModel::avatarChanged);