Bump up version to 3.9

Signed-off-by: Deokgyu Yang <secugyu@gmail.com>
diff --git a/version.h b/version.h
index 727c7e5..062afe1 100644
--- a/version.h
+++ b/version.h
@@ -1,3 +1,3 @@
-#define VERSION "3.8"
+#define VERSION "3.9"
 #define VERSION_MAJOR 3
-#define VERSION_MINOR "8"
+#define VERSION_MINOR "9"