Update number of flags.

Author: blommegard

README.md

@@ -45,7 +45,7 @@ Have a question? Please [open an issue](https://github.com/madebybowtie/FlagKit/
 
 ## Reference
 
-This set currently includes the 255 flags below:
+This set currently includes the 256 flags below:
 
 | Flag | Code | Region |
 | :-------------: | :-------------: | ------------- |