net/ruby-train-core: update to 3.7.2

3.7.2 (2021-05-24)

Merged Pull Requests
* Remove ruby 2.4 support and udpated activesupport to be >= 6.0.0 #680
  (Vasu1105)
* Add support for Ubios #687 (tas50)

3.7.0 (2021-04-28)

Merged Pull Requests

* Update chefstyle requirement from 1.7.4 to 1.7.5 #678 (dependabot[bot])
* Switch to GNU timeout-based implementation of SSH timeouts #679
  (clintoncwolfe)
* Read the username and port from /.ssh/config file and replace if present
  #659 (sanga1794)

(taca)