Update CONTRIBUTING.rst
Update CONTRIBUTING.rst
ctk3b/mbuild,ctk3b/mbuild,sallai/mbuild,Jonestj1/mbuild,summeraz/mbuild,summeraz/mbuild,iModels/mbuild,tcmoore3/mbuild,sallai/mbuild,Jonestj1/mbuild,iModels/mbuild,tcmoore3/mbuild