Bump quickbooks-ruby

Hopefully fix weird java exception returned by quickbooks

    An application error has occurred while processing your request:
        System Failure Error: java.lang.NullPointerException /Users/huoxito/.gem/ruby/2.0.0/bundler/gems/quickbooks-ruby-6c33a6b2f670/lib/quickbooks/service/base_service.rb:253:in `parse_and_raise_exception'
Replay product cassetes
Add missing product webhook parameter to docs