Update requirements django bakery

Updates the requirements.txt to django-bakery==0.2.2 so table-stacker can pass an s3cmd config file into the publish manage.py command.  This change lets the user specify different s3 config files in the case he or she wants to push to different s3 buckets, for example.  I tried to update to the latest, v0.3.0, version of django-bakery, but this breaks the application.  I will file an issue regarding that error.