Bump version number

Update version number and fix mistake in CHANGELOG.md file.

Signed-off-by: Davide Bettio <davide.bettio@ispirata.com>

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [0.11.2] - Unreleased
+## [0.11.2] - 2020-08-31
 ### Added
 - Add device hardware id getter.
 
@@ -17,7 +17,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - More detailed return error codes.
 - Add wrappers to set values on properties interfaces.
 - Add SDK version in `astarte.h`.
-- Add device hardware id getter.
 
 ### Changed
 - Most functions will no longer return ASTARTE_ERR, but a more specific error. Code checking for