Update CHANGELOG.md for v4.0.7

Author: Chohee Kim

CHANGELOG.md

@@ -1,4 +1,10 @@
+v4.0.7 / 2019-12-02
+===================
+* [BugFix] Update yarn.lock to use latest version of core-js-compat (v.3.4.7) (@choheekim)
+
+
 v4.0.6 / 2019-12-02
+===================
 * [BugFix] Fix process validation when registering callbacks for process.error & process.exit (@choheekim)
 * [Enhancement] Add a number of total, skipped, and failed tests per module to module metadata file (@choheekim)
 * Bump ember-template-lint from 1.6.0 to 1.6.1 <dependabot[bot]>