Make the setting of terminal colors optional.

README.md

@@ -21,6 +21,7 @@ To configure the plugin, you can call `require('ayu').setup(values)`, where `val
 ```lua
 require('ayu').setup({
     mirage = false, -- Set to `true` to use `mirage` variant instead of `dark` for dark background.
+    terminal = true, -- Set to `false` to let terminal manage its own colors.
     overrides = {}, -- A dictionary of group names, each associated with a dictionary of parameters (`bg`, `fg`, `sp` and `style`) and colors in hex.
 })
 ```

lua/ayu/config.lua

@@ -1,6 +1,7 @@
 local config = {
   defaults = {
     mirage = false,
+    terminal = true,
     overrides = {},
   },
 }

lua/ayu/init.lua

@@ -309,7 +309,9 @@ function ayu.colorscheme()
   vim.g.colors_name = 'ayu'
 
   colors.generate(config.mirage)
-  set_terminal_colors()
+  if config.terminal then
+    set_terminal_colors()
+  end
   set_groups()
 end