DEV: update unicorn

DEV: update unicorn

This is a minor update to unicorn, in this update unicorn handles chunked encoding a bit more correctly according to RFC

Should have no impact, but message bus will be validated in production to confirm chunked encoding still works as expected

diff --git a/Gemfile.lock b/Gemfile.lock
index 925a89a..471bb0f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -405,7 +405,7 @@ GEM
       unf_ext
     unf_ext (0.0.7.6)
     unicode-display_width (1.6.1)
-    unicorn (5.5.3)
+    unicorn (5.5.4)
       kgio (~> 2.6)
       raindrops (~> 0.7)
     uniform_notifier (1.13.0)

GitHub sha: 35e153d8