bump to ruby 2.7.5 and alpine 3.15 for base image

[orangewolf]

rebasing #5451; Third time is the charm?

cc: @no-reply

Suggestion to add to release notes for this version

Update Ruby and Alpine version for the Docker images

There is a change in Ruby 2.7.5 that makes the very obsolete require 'enumerator' call fail. This require hasn't been necessary since ruby 1.8.7 was released, but was common practice for some time. Ruby gems like oai and edtf have not been updated to support Ruby 2.7.5 yet, so that may be a factor in merging this code. We use the following patch to make those libraries work:

sed -i '/require .enumerator./d' /usr/local/bundle/gems/oai-1.1.0/lib/oai/provider/resumption_token.rb && \
sed -i '/require .enumerator./d' /usr/local/bundle/gems/edtf-3.0.5/lib/edtf.rb

https://github.com/orgs/samvera/teams/hyrax-code-reviewers

[orangewolf]

yay! thank you both