Merge pull request #252 from mruby/dependabot/bundler/rexml-3.4.2

Author: matz

Gemfile.lock

@@ -258,7 +258,7 @@ GEM
     rb-inotify (0.11.1)
       ffi (~> 1.0)
     rchardet (1.9.0)
-    rexml (3.3.9)
+    rexml (3.4.2)
     rouge (3.30.0)
     rubyzip (2.3.2)
     safe_yaml (1.0.5)