fix mvitv2 arxiv link
fix mvitv2 arxiv link

Reviewed By: wat3rBro

Differential Revision: D37653071

fbshipit-source-id: c25bb70bdd2576bc78cf903d8f39f3694cab3d2b

facebookresearch/detectron2,facebookresearch/detectron2,facebookresearch/detectron2