Update list of maintainers in governance.rst

Author: apdavison

doc/source/governance.rst

@@ -38,6 +38,7 @@ The current maintainers are:
 - Julia Sprenger (`@JuliaSprenger`_)
 - Michael Denker (`@mdenker`_)
 - Alessio Buccino (`@alejoe91`_)
+_ Zach McKenzie (`@zm711`_)
 
 
 .. _`Neo maintainers team`: https://github.com/orgs/NeuralEnsemble/teams/neo-maintainers
@@ -47,3 +48,4 @@ The current maintainers are:
 .. _`@JuliaSprenger`: https://github.com/JuliaSprenger
 .. _`@mdenker`: https://github.com/mdenker
 .. _`@alejoe91`: https://github.com/alejoe91
+.. _`@zm711`: https://github.com/zm711