add changelog entry

Author: cognifloyd

CHANGELOG.rst

@@ -4,6 +4,15 @@ Changelog
 in development
 --------------
 
+Added
+~~~~~
+
+* Continue introducing `pants <https://www.pantsbuild.org/docs>`_ to improve DX (Developer Experience)
+  working on StackStorm, improve our security posture, and improve CI reliability thanks in part
+  to pants' use of PEX lockfiles. This is not a user-facing addition.
+  #5778
+  Contributed by @cognifloyd
+
 
 3.8.0 - November 18, 2022
 -------------------------