Update CREDITS.md to include Billy O'Neal

Added acknowledgment for Billy O'Neal's contributions.

Author: orange-cpp

CREDITS.md

@@ -4,6 +4,7 @@ Thanks to everyone who made this possible, including:
 
 - Saikari aka luadebug for VCPKG port and awesome new initial logo design.
 - AmbushedRaccoon for telegram post about omath to boost repository activity.
+- Billy O'Neal aka BillyONeal for fixing compilation issues due to C math library compatibility.
 
 And a big hand to everyone else who has contributed over the past!