Bumped version to 0.20.0

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.7)
 project(libdatachannel
-	VERSION 0.19.5
+	VERSION 0.20.0
 	LANGUAGES CXX)
 set(PROJECT_DESCRIPTION "C/C++ WebRTC network library featuring Data Channels, Media Transport, and WebSockets")