update readme file

Author: vishaltps

README.md

@@ -44,7 +44,7 @@ A lightweight, zero-dependency web interface for monitoring Solid Queue backgrou
 Add this line to your application's Gemfile:
 
 ```ruby
-gem 'solid_queue_monitor', '~> 0.3.0'
+gem 'solid_queue_monitor', '~> 0.3.1'
 ```
 
 Then execute: