Change transition input field to a dropdown listing all the possible transition

Description

Currently, when activating the JIRA plugin, we need define the transition, which is the state the issue will be in JIRA once we close it in GitLab. The transition is not easy to find in JIRA, and at the moment, it's a number like below. It's not user friendly at all.

image

Specification

  • Pull all the possible transitions from their API (we can do it with our new gem)
  • Display all the transitions in a dropdown
  • The Transitions dropdown should list the label, not the number.