Merge pull request #277 from StatProofBook/dependabot/bundler/rexml-3.3.9

Bump rexml from 3.3.6 to 3.3.9

Author: StatProofBook

Gemfile.lock

@@ -59,16 +59,14 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
-    rexml (3.3.6)
-      strscan
+    rexml (3.3.9)
     rouge (3.9.0)
     ruby_dep (1.5.0)
     safe_yaml (1.0.5)
     sassc (2.1.0)
       ffi (~> 1.9)
     sassc (2.1.0-x64-mingw32)
       ffi (~> 1.9)
-    strscan (3.1.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)