libyang CHANGE review header includes

The plugins_types.h was supposed only for implementing data type plugins
code, so I've removed it from libyang.h (now it is supposed to be
included explicitly).
diff --git a/src/plugins_exts.c b/src/plugins_exts.c
index f5e3ce4..2bf6889 100644
--- a/src/plugins_exts.c
+++ b/src/plugins_exts.c
@@ -14,6 +14,7 @@
 
 #include "plugins_exts.h"
 
+#include <stdint.h>
 #include <string.h>
 
 #include "common.h"