Merge pull request #228 from mruby/dependabot/bundler/rexml-3.3.6

Author: matz

Gemfile.lock

@@ -254,7 +254,7 @@ GEM
     rb-inotify (0.11.1)
       ffi (~> 1.0)
     rchardet (1.8.0)
-    rexml (3.3.4)
+    rexml (3.3.6)
       strscan
     rouge (3.30.0)
     rubyzip (2.3.2)