README: Add Vinegar to apps list

Vinegar is a bootstrapper for Roblox Player and Roblox Studio. It uses gamemode for both by default.

README.md

@@ -80,7 +80,7 @@ Other apps which can integrate with GameMode include:
 * Lutris - Enables GameMode for all games by default if available (must have both 32- and 64-bit GameMode libraries installed), configurable in preferences.
 * [Prism Launcher](https://prismlauncher.org/) Minecraft launcher
 * [RetroArch](https://www.retroarch.com) - is a frontend for emulators, game engines and media players.
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+* [Vinegar](https://vinegarhq.org/) - Roblox Player/Studio bootstrapper.
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 ## Development [![Build and test](https://github.com/FeralInteractive/gamemode/actions/workflows/build-and-test.yml/badge.svg)](https://github.com/FeralInteractive/gamemode/actions/workflows/build-and-test.yml)