Update history.txt

megamek/docs/history.txt

@@ -101,6 +101,7 @@ MEGAMEK VERSION HISTORY:
 + PR #5919: A simple test that checks canonicity is working as intended
 + PR #5925: Fix to make mech file parser canon check unit testable in IDE
 + PR #5929: Fix ammo auto config for Artemis skipping SRMs and MMLs
++ Fix #5903: null check before dereferencing Coords
 
 0.49.20 (2024-06-28 2100 UTC) (THIS IS THE LAST VERSION TO SUPPORT JAVA 11)
 + PR #5281, #5327, #5308, #5336, #5318, #5383, #5369, #5384, #5455, #5505, #5541: Code internals: preparatory work for supporting game types such as SBF, code cleanup for string drawing, superclass change for BoardView,