Update changelog

Author: jeffgbutler

CHANGELOG.md

@@ -17,6 +17,7 @@ If you have written your own set of functions to extend the library, you will no
 - Added a general insert statement that does not require a separate record class to hold values for the insert. ([#201](https://github.com/mybatis/mybatis-dynamic-sql/issues/201))
 - Added the capability to specify a rendering strategy on a column to override the defaut rendering strategy for a statement. This will allow certain edge cases where a parameter marker needs to be formatted in a unique way (for example, "::jsonb" needs to be added to parameter markers for JSON fields in PostgreSQL) ([#200](https://github.com/mybatis/mybatis-dynamic-sql/issues/200))
 - Added the ability to write a function that will change the column data type ([#197](https://github.com/mybatis/mybatis-dynamic-sql/issues/197))
+- Added the `applyOperator` function to make it easy to use non-standard database operators in expressions ([#220](https://github.com/mybatis/mybatis-dynamic-sql/issues/220))
 
 ## Release 1.1.4 - November 23, 2019