1.2.0 readiness

- Set date in CHANGELOG
- Updated `composer.json`:
  - Use `^5.4.8 || ^7.0` for PHP requirement
  - Update branch aliases:
    - dev-master => 1.2-dev
    - dev-develop => 1.3-dev

CHANGELOG.md

@@ -6,7 +6,7 @@ Versions prior to 1.0 were originally released as `phly/conduit`; please visit
 its [CHANGELOG](https://github.com/phly/conduit/blob/master/CHANGELOG.md) for
 details.
 
-## 1.2.0 - TBD
+## 1.2.0 - 2016-03-17
 
 This release contains two potential backwards compatibility breaks:
 

composer.json

@@ -15,12 +15,12 @@
   },
   "extra": {
     "branch-alias": {
-      "dev-master": "1.0-dev",
-      "dev-develop": "1.1-dev"
+      "dev-master": "1.2-dev",
+      "dev-develop": "1.3-dev"
     }
   },
   "require": {
-    "php": ">=5.4.8",
+    "php": "^5.4.8 || ^7.0",
     "psr/http-message": "~1.0.0",
     "zendframework/zend-escaper": "~2.3"
   },