v3.8.0 brief changelog entry referencing NREL#344

Author: softwareengineerprogrammer

CHANGELOG.rst

@@ -5,6 +5,14 @@ Changelog
 GEOPHIRES-X (2023-2025)
 ------------------------
 
+3.8
+^^^
+
+`release <https://github.com/NREL/GEOPHIRES-X/releases/tag/v3.8.0>`__ | `diff <https://github.com/NREL/GEOPHIRES-X/compare/v3.7.0...v3.8.0>`__
+
+Revenue & Cashflow Profile period output aligned with NREL convention used to calculate NPV.
+See https://github.com/NREL/GEOPHIRES-X/discussions/344
+
 3.7
 ^^^