Update Nokogiri to fix vulnerability

Name: nokogiri
Version: 1.10.1
Advisory: CVE-2019-11068
Criticality: Unknown
URL: sparklemotion/nokogiri#1892
Title: Nokogiri gem, via libxslt, is affected by improper access control vulnerability
Solution: upgrade to >= 1.10.3

Gemfile.lock

@@ -255,7 +255,7 @@ GEM
       rails (>= 3.2.0)
     net-ldap (0.16.1)
     nio4r (2.3.1)
-    nokogiri (1.10.1)
+    nokogiri (1.10.3)
       mini_portile2 (~> 2.4.0)
     paper_trail (10.2.1)
       activerecord (>= 4.2, < 6.1)