Upgrade passenger container version

[kerchner]

Passenger startup log includes the following:
A security update is available for your version (6.0.17) of Phusion Passenger(R). We strongly recommend upgrading to version 6.0.20

This would entail upgrading our base image from phusion/passenger-ruby27:2.5.0 to phusion/passenger-ruby30:3.0.1 as the last ruby27 based container (2.5.1) only upgrades to Passenger 6.0.18. Likely will require changes to https://github.com/gwu-libraries/scholarspace-hyrax/blob/master/Dockerfile#L36 as well.

See https://github.com/phusion/passenger-docker/blob/master/CHANGELOG.md