Update GDK default labels for new merge requests and issues

Summary

Ecosystem has moved from a group label to a stage label. Lets add the new group and stage labels by default

GDK development also recently moved to the Engineering Productivity team. So we should use that label as the default

References

Related to #718 (closed)

Action items

• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Week-in-review