2.9.0 readiness

- Updated branch aliases
  - dev-master => 2.9.x-dev
  - dev-develop => 2.10.x-dev
- Updated CHANGELOG
  - Removed empty 2.8.1 stub
  - Set date for 2.9.0

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 2.9.0 - TBD
+## 2.9.0 - 2019-12-27
 
 ### Added
 
@@ -26,28 +26,6 @@ Disables use of BigInteger for XMLRPC i8 type if host machine is 64-bit.
 
 - Nothing.
 
-## 2.8.1 - TBD
-
-### Added
-
-- Nothing.
-
-### Changed
-
-- Nothing.
-
-### Deprecated
-
-- Nothing.
-
-### Removed
-
-- Nothing.
-
-### Fixed
-
-- Nothing.
-
 ## 2.8.0 - 2019-10-19
 
 ### Added

composer.json

@@ -49,8 +49,8 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.8.x-dev",
-            "dev-develop": "2.9.x-dev"
+            "dev-master": "2.9.x-dev",
+            "dev-develop": "2.10.x-dev"
         }
     },
     "scripts": {