Erratum: Magnetostriction of helimagnets in the skyrmion crystal phase (2019 New J. Phys.21 123052). (6th March 2020) - Wang, Shasha; Hu, Yangfan; Tang, Jin; Wei, Wensen; Cong, Junzhuang; Sun, Young; Du, Haifeng; Tian, Mingliang