update submodule zighttp

diff --git a/ext/zighttp b/ext/zighttp
index 274c46eb3f7e9987cc9260bb70c43b4f5d8555ac..d2215f174d1c9c8a66c62094d99e1c8d2305b1c1 160000 (submodule)
--- a/ext/zighttp
+++ b/ext/zighttp
@@ -1 +1 @@
-Subproject commit 274c46eb3f7e9987cc9260bb70c43b4f5d8555ac
+Subproject commit d2215f174d1c9c8a66c62094d99e1c8d2305b1c1