New AUTHORS.md file

This file lists specific copyright holders and project maintainers.
It will also include any future contributors.

AUTHORS.md

@@ -0,0 +1,10 @@
+**Project:** `pybricks-api`
+
+**The Pybricks Authors (copyright holders of this project):**
+- Laurens Valk
+- David Lechner
+- LEGO System A/S
+
+**Maintainers:**
+- Laurens Valk (@laurensvalk)
+- David Lechner (@dlech)