Updated HISTORY.md.

Author: ggarra13

src/docs/HISTORY.md

@@ -87,6 +87,8 @@ v1.3.8
 - Fixed and simplified code for NDIView (hdr utility).
 - Fixed hdr utility for macOS Intel trying to pass full HDR10 or HLG data, 
   which goes over those machines' nits.
+- Fixed a problem in first release of v1.3.8 regarding Input Color Space
+  failing when first switched on.
 
 v1.3.7
 ======