Automated submodule update: vrs (#117)

Summary:
This is an automated pull request to update the first-party submodule for [facebookresearch/vrs](https://github.com/facebookresearch/vrs).

New submodule commit: facebookresearch/vrs@efd5600

Pull Request resolved: #117

Test Plan: Ensure that CI jobs succeed on GitHub before landing.

Reviewed By: georges-berenger

Differential Revision: D64012494

fbshipit-source-id: 42d08232a71300ad8b77e9d593340ec1e15487ed