Add gaijin domains (#3257)

Close https://github.com/v2fly/domain-list-community/issues/3190

data/category-games-!cn

@@ -9,6 +9,7 @@ include:eneba
 include:epicgames
 include:escapefromtarkov
 include:faceit
+include:gaijin
 include:garena
 include:gog
 include:hoyoverse