add @Volt220 to credits

Author: idelvall

CREDITS

@@ -1,10 +1,14 @@
 Here are people who have contributed to development of json-forms
 (version numbers in brackets indicate release in which the problem was fixed)
 
-Omri Schwarz (ocschwar@github):
-#11: Add handling for the oneOf option for schemas
-(1.2.0)
+Volt220@github
+#15: Update brutusin-json-forms.css
+(1.2.3)
 
 Dirk Haage (e110c0@github)
 #14 Added version to package.json
 (1.2.1)
+
+Omri Schwarz (ocschwar@github):
+#11: Add handling for the oneOf option for schemas
+(1.2.0)