Update Makefile RAYLIB_VERSION (#3901)

Changed the raylib version from 4.2.0 to 5.1-dev, just like the raylib.h file

projects/VSCode/Makefile

@@ -25,7 +25,7 @@
 
 # Define required raylib variables
 PROJECT_NAME       ?= game
-RAYLIB_VERSION     ?= 4.2.0
+RAYLIB_VERSION     ?= 5.1-dev
 RAYLIB_PATH        ?= ..\..
 
 # Define compiler path on Windows