removing mismatch() event from ValidationListener since it is currently not supported

Author: erosb

core/src/main/java/org/everit/json/schema/event/ValidationListener.java

@@ -8,9 +8,6 @@ public interface ValidationListener {
     ValidationListener NOOP = new ValidationListener() {
     };
 
-    default void mismatch(MismatchEvent event) {
-    }
-
     default void combinedSchemaMatch(CombinedSchemaMatchEvent event) {
     }