FIX: update mini racer to correct heap dumps

FIX: update mini racer to correct heap dumps

This corrects an issue where mini racer’s write_heap_snapshot produces corrupt heaps cause the file is not flushed.

diff --git a/Gemfile.lock b/Gemfile.lock
index 87d71f7..ce187c8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -188,7 +188,7 @@ GEM
     method_source (1.0.0)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
-    mini_racer (0.2.10)
+    mini_racer (0.2.11)
       libv8 (> 7.3)
     mini_scheduler (0.12.2)
       sidekiq

GitHub sha: 5b603cb3