add changelog

Author: braingram

CHANGES.rst

@@ -6,6 +6,7 @@
   format whereas the ASDF core schemas refers to the versioned
   collection of schemas for core objects (ndarray, software, etc) [#473]
 - Add datatype-1.0.0 schema [#455]
+- Add galexsec time to time-1.4.0 [#480]
 
 1.3.0 (2025-06-11)
 ------------------