2.0.0 readiness

- Updates branch aliases:
  - dev-master => 2.0.x-dev
  - dev-develop => 2.1.x-dev
- Updates CHANGELOG
  - Adds 2.0.0 section
  - Sets date for 2.0.0 release

Author: weierophinney

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 2.0.0 - TBD
+## 2.0.0 - 2019-12-28
 
 ### Added
 

composer.json

@@ -53,8 +53,8 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "1.3.x-dev",
-            "dev-develop": "2.0.x-dev"
+            "dev-master": "2.0.x-dev",
+            "dev-develop": "2.1.x-dev"
         },
         "zf": {
             "config-provider": "Zend\\Expressive\\Authentication\\OAuth2\\ConfigProvider"