Improve our CI/CD pipeline to add a Dev stage

[TimothyXu]

As a developer I need to have a better CI/CD pipeline So that I spend even less time worrying about things that's not coding

Details and Assumptions

• Dev stage should automatically deploy our app in a Dev environment only if the nosetests from Build stage passes.

• Can append -dev to the dev instance

  Acceptance Criteria

  Given we have set up a dev stage
  And our app passes nosetests
  When we make new commit on main branch in GitHub
  Then IBM Cloud automatically deploys an instance of our app in a development environment

[TimothyXu]

No PR attached but this is done: dev instance running at: https://nyu-shopcart-service-sp2203-dev.us-south.cf.appdomain.cloud Have set up CI/CD to automatically build test and deploy to dev instance whenever main branch is updated. Production instance which will use https://nyu-shopcart-service-sp2203.us-south.cf.appdomain.cloud are to be set up in the last 2 stages of CI/CD in separate stories