[VERSION] update version to 2.6.0

Author: gwanglst

lsqpack.h

@@ -43,8 +43,8 @@ extern "C" {
 #endif
 
 #define LSQPACK_MAJOR_VERSION 2
-#define LSQPACK_MINOR_VERSION 5
-#define LSQPACK_PATCH_VERSION 5
+#define LSQPACK_MINOR_VERSION 6
+#define LSQPACK_PATCH_VERSION 0
 
 /** Let's start with four billion for now */
 typedef unsigned lsqpack_abs_id_t;