update modification object in ldap.change (#910)

* updated the modification object in ldap.change

* Adding Change Interface

* Modification reference table

docs/client.md

@@ -213,7 +213,8 @@ Example:
 const change = new ldap.Change({
   operation: 'add',
   modification: {
-    pets: ['cat', 'dog']
+    type: 'pets',
+    values: ['cat', 'dog']
   }
 });
 
@@ -234,7 +235,13 @@ must be one of:
 | add       | Adds the attribute value(s) referenced in `modification`.  The attribute may or may not already exist. |
 | delete    | Deletes the attribute (and all values) referenced in `modification`. |
 
-`modification` is just a plain old JS object with the values you want.
+`modification` is just a plain old JS object with the required type and values you want.
+
+| Operation | Description |
+|-----------|-------------|
+| type      | String that defines the attribute type for the modification. |
+| values    | Defines the values for modification. |
+
 
 # modifyDN
 `modifyDN(dn, newDN, controls, callback)`