bump gossamer commit

diff --git a/gossamer b/gossamer
index d20b175402551f03ee886145b02e09295df99617..64e8e93e0c7bb42c08c114edc5c38584e8b77795 160000 (submodule)
--- a/gossamer
+++ b/gossamer
@@ -1 +1 @@
-Subproject commit d20b175402551f03ee886145b02e09295df99617
+Subproject commit 64e8e93e0c7bb42c08c114edc5c38584e8b77795