Maintenance: Update dependency rchardet to v1.9.0

Gemfile.lock

@@ -546,7 +546,7 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rchardet (1.8.0)
+    rchardet (1.9.0)
     rdoc (6.7.0)
       psych (>= 4.0.0)
     redis (4.8.1)