Update hammer to fix `cargo build -h`.

diff --git a/libs/hammer.rs b/libs/hammer.rs
index ce9e79abe94407abc155be13340d7a72ac5198d0..3e6218afdc17dcdd456f7ad2be38e2fbba493983 160000 (submodule)
--- a/libs/hammer.rs
+++ b/libs/hammer.rs
@@ -1 +1 @@
-Subproject commit ce9e79abe94407abc155be13340d7a72ac5198d0
+Subproject commit 3e6218afdc17dcdd456f7ad2be38e2fbba493983