Bump to version 3.1.1

Author: andreamazz

BubbleTransition.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = 'BubbleTransition'
-  s.version = '3.1.0'
+  s.version = '3.1.1'
   s.license = 'MIT'
   s.summary = 'A custom modal transition that presents and dismiss a controller with a bubble effect'
   s.description  = <<-DESC

CHANGELOG.md

@@ -2,14 +2,18 @@
 All notable changes to this project will be documented in this file.
 `BubbleTransition` adheres to [Semantic Versioning](http://semver.org/).
 
-- `3.1.x` Releases - [3.1.0](#310)  
+- `3.1.x` Releases - [3.1.0](#310) | [3.1.1](#311)  
 - `3.0.x` Releases - [3.0.0](#300) | [3.0.1](#301) | [3.0.2](#302)  
 - `2.0.x` Releases - [2.0.0](#200) | [2.0.1](#201) | [2.0.2](#202)  
 - `1.0.x` Releases - [1.0.0](#100) | [1.0.1](#101) | [1.0.2](#102) | [1.0.3](#103)   
 - `0.2.x` Releases - [0.2](#02)
 
 ---
 
+## [3.1.1](https://github.com/andreamazz/BubbleTransition/releases/tag/3.1.1)
+
+- Merged #48  
+
 ## [3.1.0](https://github.com/andreamazz/BubbleTransition/releases/tag/3.1.0)
 
 - Added `BubbleInteractiveTransition`