Update dependencies for April 2021

[DeeDeeG]

Context

• Bumping a few JavaScript (NodeJS) and Ruby package dependencies, as well as bumping the versions of Ruby and Rails.

Summary of Changes

• In the yarn.lock lockfile for our JavaScript package dependencies...
  • Update postcss-svgo from 4.0.2 to 4.0.3
  • Thereby dropping the is-css and html-comment-regex sub-dependencies
  • Update ssri to the latest 6.x (6.0.2) and 8.x (8.0.1) versions
  • Update y18n from 4.0.0 to 4.0.3
• In the Gemfile.lock lockfile for our Ruby package dependencies...
  • Update rexml from 3.2.4 to 3.2.5
• Update Rails from 5.2.4.5 to 5.2.5
• Update Ruby from 2.7.2 to 2.7.3

Checklist

• [x] Tested Mobile Responsiveness
• [ ] Added Unit Tests
• [x] CI Passes
• [x] Deploys to Heroku on test Correctly (Maintainers will handle)
• [ ] Added Documentation (Service and Code when required)