This mod adds all the primary armor colors to the secondary ones. 

INSTALLATION INSTRUCTIONS
Copy folder to your SteamPath/XCOM 2/XComGame/Mods/
UNINSTALL INSTRUCTIONS
1: Delete from mods folder
2: Sometimes the game does not remove config settings properly upon uninstalling. To get around this you need to open your: 
Documents/my games/XCOM2/XComGame/Config/XComContent.ini 
and replace:
ColorPaletteInfo=(Palette=ePalette_ArmorTint,ArchetypeName="Expandedarmorcolors.ArmorTint")")
with
ColorPaletteInfo=(Palette=ePalette_ArmorTint,ArchetypeName="X2_UnitPalettes.ArmorTint")