Require Laravel 5.2, but not Laravel 5.3
The Docker Image doesn't build, as at artisan optimize step,
a fatal error occurs, as our EventServiceProvider::boot() isn't
compatible anymore with parent class signature.
This is caused by two factors:
- upstream: commit fa9f3220 made the class boot method now use facades instead of dependency injection to the method
- locally: commit d69820ed127c required Laravel 5.2.41+ to get session code update, but didn't guard agaisnt 5.3.*
We require 5.2.*, using ~ and not ^ in Composer version syntax.
The caret operator is more appropraited when semver is better followed.
Test Plan: Ensure composer install latest 5.2.
Maniphest Tasks: T997
Differential Revision: https://devcentral.nasqueron.org/D638