[Librarian] Version Bump

Author: twilio-ci

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+[2020-12-16] Version 6.3.8
+--------------------------
+**Library - Fix**
+- [PR #448](https://github.com/sendgrid/sendgrid-ruby/pull/448): tests failing on rubocop rule. Thanks to [@thinkingserious](https://github.com/thinkingserious)!
+
+
 [2020-11-05] Version 6.3.7
 --------------------------
 **Library - Chore**