Merge pull request #224 from ohbarye/dependabot/bundler/backend/nokogiri-1.10.5

[Security] Bump nokogiri from 1.10.4 to 1.10.5 in /backend

Author: ohbarye

backend/Gemfile.lock

@@ -101,7 +101,7 @@ GEM
     minitest (5.11.3)
     msgpack (1.3.1)
     nio4r (2.5.2)
-    nokogiri (1.10.4)
+    nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
     public_suffix (4.0.1)