Add PR link to CHANGELOG.md

Author: jeffgbutler

CHANGELOG.md

@@ -26,6 +26,7 @@ GitHub milestone: [https://github.com/mybatis/mybatis-dynamic-sql/issues?q=miles
    will be well worth the effort to migrate to the new DSL. The prior where clause DSL remains in the library for now,
    but is deprecated. It will be removed in version 1.5.0 of the library. Documentation for the new DSL is here:
    https://github.com/mybatis/mybatis-dynamic-sql/blob/master/src/site/markdown/docs/kotlinWhereClauses.md
+   ([#442](https://github.com/mybatis/mybatis-dynamic-sql/pull/442))
 
 ## Release 1.3.1 - December 18, 2021