Update ADOPTERS.md
Add OLX Brasil to ADOPTERS.md
- [Vernacular.ai](https://vernacular.ai/)
- [xCloud](https://www.xbox.com/en-US/xbox-game-streaming/project-xcloud)
- [YouMail](https://www.youmail.com)
+- [OLX Brasil](https://www.olx.com.br)
If you're using Linkerd 2.x and aren't on this list, please [submit a pull
request](https://github.com/linkerd/linkerd2/edit/main/ADOPTERS.md)!
