libyang CHANGE headers includes cleanup using include-what-you-use tool (#1098)

diff --git a/tests/utests/schema/test_printer_yin.c b/tests/utests/schema/test_printer_yin.c
index 9dbec76..9991e0f 100644
--- a/tests/utests/schema/test_printer_yin.c
+++ b/tests/utests/schema/test_printer_yin.c
@@ -21,6 +21,7 @@
 #include <string.h>
 
 #include "../../src/context.h"
+#include "../../src/printer.h"
 #include "../../src/printer_schema.h"
 
 #define BUFSIZE 1024