use a pack version that has proper mysql encoding

diff --git a/pack b/pack
index e2c33af..c5c37fa 160000 (submodule)
--- a/pack
+++ b/pack
@@ -1 +1 @@
-Subproject commit e2c33af7744b42cf33e9e40e3a2ab4b93dc09cc2
+Subproject commit c5c37fac1ab6c56d4879d74808a6ae9f44384bda