Merge pull request #6 from wp-cli/correct-dev-master-alias

Correct `dev-master` alias.

Author: danielbachhuber

composer.json

@@ -28,7 +28,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "1.0.x-dev"
+            "dev-master": "1.x-dev"
         },
         "commands": [
             "db create",