Revise BrainVISA development environment setup

Updated instructions for setting up BrainVISA developer environment using Pixi.

Author: denisri

devenv_pixi.md

@@ -2,5 +2,9 @@
 title: Development environment for BrainVISA 6
 ---
 
-> [!NOTE]
-> This development environment is still under test, it is planned to be used for BrainVISA 6.
+Installing a BrainVisa developer environment is now done using Pixi.
+It consists in cloning [the soma-env repository from github](https://github.com/brainvisa/soma-env), starting a pixi shell in it, then running the `bv_maker` command.
+The full instructions are there on the github repository:
+https://github.com/brainvisa/soma-env
+
+**Note** that the new stabilized branches are the `6.0` set of branches, which should be preferred (to `main`/`master`) unless reworking major changes in the libraries.