release notes updated

Author: Nabil Fayak

docs/source/release_notes.rst

@@ -11,6 +11,7 @@ Release Notes
     * Enhancements
         * Added all datachecks except `invalid_target_data_check` along with tests and utils, migrated over from `EvalML` :pr:`15`
         * Added ``invalid_target_data_check`` along with all tests, utils, and objectives, migrated from ``EvalML`` :pr:`17`
+        * Added modules necessary to remove ``EvalML`` dependencies within testing environment :pr:`19`
     * Documentation Changes
         * Updated readme.md, contrubuting.md, and releases.md to reflect CheckMates package installation, quickstart, and useful links :pr:`13`