Merge pull request #1240 from pkp/dependabot/bundler/rexml-3.3.3

Bump rexml from 3.2.8 to 3.3.3

Author: emmauhl

Gemfile.lock

@@ -60,8 +60,8 @@ GEM
     rb-fsevent (0.11.1)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.8)
-      strscan (>= 3.0.9)
+    rexml (3.3.3)
+      strscan
     rouge (3.28.0)
     safe_yaml (1.0.5)
     sassc (2.4.0)