CHANGELOG.md in dns_mock-1.2.0 vs CHANGELOG.md in dns_mock-1.2.1

@@ -1,18 +1,27 @@
 # Changelog
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.2.1] - 2021-03-23
+
+### Changed
+
+- Updated gem development dependencies
+- Updated rubocop/codeclimate config
+- Updated gem documentation
+- Updated tests
+
 ## [1.2.0] - 2021-02-04
 
 ### Ability to specify MX record priority
 
 Added ability to specify custom priority of MX record if it needed. Now it impossible to define null or backup MX records. Please note, if you haven't specified a priority of MX record, it will be assigned automatically. MX records builder is assigning priority with step 10 from first item of defined MX records array.
 
 ```ruby
 records = {
   'example.com' => {
-    mx: %w[.:0 mx1.domain.com:10 mx2.domain.com:10 mx3.domain.com]
+    mx: %w[.:0 mx1.domain.com:10 mx2.domain.com:10 mx3.domain.com] # .:0 - null MX record
   }
 }
 
 DnsMock.start_server(records: records)
 ```