bump packages for feature parity with heroku

Taken straight from https://github.com/heroku/stack-images/blob/master/bin/cedar-14.sh#L16-L55, this bumps us up to feature parity with Heroku's beta cedar stack. Interesting to note that they removed Java 6 support...

I intentionally left in `pigz` due to 304a97d831, though I would argue that Heroku does not have this package installed, so we shouldn't either. Up to you.