Bump rexml from 3.2.6 to 3.4.1 (#359)

Author: alexandrule

Gemfile.lock

@@ -31,7 +31,7 @@ GEM
     racc (1.8.1)
     rainbow (3.1.1)
     regexp_parser (2.10.0)
-    rexml (3.3.3)
+    rexml (3.4.1)
       strscan
     rspec (3.9.0)
       rspec-core (~> 3.9.0)