Merge pull request #240 from rabbitmq/dependabot/bundler/rexml-3.3.9

Bump rexml from 3.3.8 to 3.3.9

Author: michaelklishin

Gemfile.lock

@@ -107,7 +107,7 @@ GEM
       racc (~> 1.4)
     public_suffix (4.0.7)
     racc (1.8.1)
-    rexml (3.3.8)
+    rexml (3.3.9)
     ruby-macho (2.5.1)
     securerandom (0.3.1)
     typhoeus (1.4.1)