Update packages.php

solves https://github.com/clevertech/YiiBooster/issues/672
Merge pull request #673 from fleuryc/patch-1

Update packages.php
Merge branch '1.1.0' of github.com:clevertech/YiiBooster into 1.1.0
Merge branch '1.1.0'
Updated version to 3.0.0~alpha, we're going to release version 3 with a small stop at 2.1.0