update vkh

diff --git a/vkh b/vkh
index 0a1ffaf552f116b0990c4968760de494b0ad5a9e..677a3547d5a930494177aeb4f9e802922dc975c3 160000 (submodule)
--- a/vkh
+++ b/vkh
@@ -1 +1 @@
-Subproject commit 0a1ffaf552f116b0990c4968760de494b0ad5a9e
+Subproject commit 677a3547d5a930494177aeb4f9e802922dc975c3