Automated submodule update: vrs (facebookresearch#138)

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@b0d241b

Pull Request resolved: facebookresearch#138

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

Reviewed By: georges-berenger

Differential Revision: D67405553

fbshipit-source-id: 2dd74407cdf2ee1ca876be3bd12b5910e457533f