chore: add lbarthon & migueldemoura to maintainers

As the core maintainers of this project became less active, Miguel de Moura and
myself became more active on here. This updates the official maintainers list
to reflect what has been happening over a bit more than a year.

README.md

@@ -11,6 +11,8 @@ Maintainers
 * [Com Menthol](https://github.com/commenthol)
 * [Lindsey Simon](https://github.com/elsigh) ([@elsigh](https://twitter.com/elsigh))
 * [Tobie Langel](https://github.com/tobie) ([@tobie](https://twitter.com/tobie))
+* [Louis Barthonet](https://github.com/lbarthon)
+* [Miguel de Moura](https://github.com/migueldemoura)
 
 Communication channels
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