Add documentation about disabling colors to readme

Author: kodie

README.md

@@ -508,6 +508,13 @@ Ahc\Cli\Output\Color::style('error', [
 ]);
 ```
 
+#### Disable colors
+
+```php
+Ahc\Cli\Output\Color::$colors_enabled = false;
+```
+
+
 ### Cursor
 
 Move cursor around, erase line up or down, clear screen.