Update gem rubyzip to 2.4.1 (#2348)

Signed-off-by: David A. Wheeler <[email protected]>

Author: david-a-wheeler

Gemfile.lock

@@ -481,7 +481,7 @@ GEM
     ruby-graphviz (1.2.5)
       rexml
     ruby-progressbar (1.13.0)
-    rubyzip (2.3.2)
+    rubyzip (2.4.1)
     rugged (1.7.2)
     sassc (2.4.0)
       ffi (~> 1.9)