Add project: mpv

[RossSmyth]

Basic info

Project name: mpv
Project link: https://github.com/mpv-player/mpv

Qualifications

ZeroVer's patent-pending zero-based versioning
scheme can obviously be used by everyone, but not every usage is
necessarily notable. Check that the first and at least one other
criterion apply:

• A current ZeroVer-compliant version (0.*) or long history of ZeroVer usage, and
• Very wide exposure (i.e., 1,000+ GitHub stars), or
• Active promotion as part of a paid product or service (e.g., Hashicorp Vault), or
• Relative maturity and infrastructural importance (e.g., Compiz, docutils)