Update CODE_OF_CONDUCT.md

Update CODE_OF_CONDUCT.md

Author: b-g

CODE_OF_CONDUCT.md

@@ -22,6 +22,7 @@ As we have a limited amount of energy for moderation there are some contribution
 
 - Any kind of historical or official "military insignia" e.g. Swastika, German Army (Deutsches Heer), Royal Air Force, US Navy
 - Flags of countries not recognized by the UN e.g. Tibet
+- Flags of any sub-national entities e.g. München. With the exception of officially recognized "country" or "state" level regions e.g. California, Bavaria, Provence etc.
 - Historic flags of states e.g. East Germany (Deutsche Demokratische Republik), Yugoslavia, Confederate States of America
 - Religious images that are not in the Unicode standard or violate one of the above e.g. the Swastika is a religious symbol in Unicode but it violates the military insignia rule
 - Any sexual or erotic imagery. While our “activity” emojis are depicted in their poses without clothes, the implication is not erotic.