update coq-hetmet submodule pointer

diff --git a/compiler/hetmet b/compiler/hetmet
index 8c26722..6232ffa 160000 (submodule)
--- a/compiler/hetmet
+++ b/compiler/hetmet
@@ -1 +1 @@
-Subproject commit 8c26722a1ee110077968a8a166eb7130266b2035
+Subproject commit 6232ffa2805211654c6ff40a9852d7fc312382d2