Update version to 3.8-dev to note breaking changes

Some breaking changes were introduced lately, it's better to note that current version is not 3.7 anymore...

src/Makefile

@@ -43,8 +43,8 @@
 .PHONY: all clean install uninstall
 
 # Define required raylib variables
-RAYLIB_VERSION        = 3.7.0
-RAYLIB_API_VERSION    = 370
+RAYLIB_VERSION        = 3.8-dev
+RAYLIB_API_VERSION    = 381
 
 # Define raylib source code path
 RAYLIB_SRC_PATH      ?= ../src

src/raylib.h

@@ -81,7 +81,7 @@
 
 #include <stdarg.h>     // Required for: va_list - Only used by TraceLogCallback
 
-#define RAYLIB_VERSION  "3.7.0"
+#define RAYLIB_VERSION  "3.8-dev"
 
 #if defined(_WIN32)
     // Microsoft attibutes to tell compiler that symbols are imported/exported from a .dll