Update rexml to v3.3.9 in Gemfile.lock

Author: eby-dev

Gemfile.lock

@@ -179,7 +179,7 @@ GEM
       trailblazer-option (>= 0.1.1, < 0.2.0)
       uber (< 0.2.0)
     retriable (3.1.2)
-    rexml (3.2.8)
+    rexml (3.3.9)
       strscan (>= 3.0.9)
     rouge (2.0.7)
     ruby2_keywords (0.0.5)
@@ -211,7 +211,7 @@ GEM
       claide (>= 1.0.2, < 2.0)
       colored2 (~> 3.1)
       nanaimo (~> 0.3.0)
-      rexml (~> 3.2.8)
+      rexml (~> 3.3.9)
     xcpretty (0.3.0)
       rouge (~> 2.0.7)
     xcpretty-travis-formatter (1.0.1)