deleted method 'required()'

Author: sergeycherkasovv

app/src/main/java/hexlet/code/schemas/MapSchema.java

@@ -2,15 +2,9 @@
 
 
 import java.util.Map;
-import java.util.Objects;
 
 public final class MapSchema extends BaseSchema<Map<?, ?>> {
 
-    public MapSchema required() {
-        addValidation("required", Objects::nonNull);
-        return this;
-    }
-
     public MapSchema sizeof(int limitSize) {
         addValidation("sizeof", m -> m.size() == limitSize);
         return this;