Merge pull request #223 from mruby/dependabot/bundler/rexml-3.2.8

Bump rexml from 3.2.6 to 3.2.8

Author: matz

Gemfile.lock

@@ -246,7 +246,8 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     rchardet (1.8.0)
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (3.30.0)
     ruby2_keywords (0.0.5)
     rubyzip (2.3.2)
@@ -261,6 +262,7 @@ GEM
       faraday (>= 0.17.3, < 3)
     simpleidn (0.2.1)
       unf (~> 0.1.4)
+    strscan (3.1.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     typhoeus (1.4.1)