Bump rexml from 3.2.8 to 3.3.9 in /example (#136)

Author: dependabot[bot]

example/Gemfile.lock

@@ -75,21 +75,19 @@ GEM
     netrc (0.11.0)
     nkf (0.2.0)
     public_suffix (4.0.7)
-    rexml (3.2.8)
-      strscan (>= 3.0.9)
+    rexml (3.3.9)
     ruby-macho (2.5.1)
-    strscan (3.1.0)
     typhoeus (1.4.1)
       ethon (>= 0.9.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
-    xcodeproj (1.24.0)
+    xcodeproj (1.25.1)
       CFPropertyList (>= 2.3.3, < 4.0)
       atomos (~> 0.1.3)
       claide (>= 1.0.2, < 2.0)
       colored2 (~> 3.1)
       nanaimo (~> 0.3.0)
-      rexml (~> 3.2.4)
+      rexml (>= 3.3.6, < 4.0)
 
 PLATFORMS
   ruby