Update version to 2.5.2 .

Author: gwanglst

lsqpack.h

@@ -44,7 +44,7 @@ typedef SSIZE_T ssize_t;
 
 #define LSQPACK_MAJOR_VERSION 2
 #define LSQPACK_MINOR_VERSION 5
-#define LSQPACK_PATCH_VERSION 1
+#define LSQPACK_PATCH_VERSION 2
 
 /** Let's start with four billion for now */
 typedef unsigned lsqpack_abs_id_t;