Explicit stage is required with needs

Summary

When using needs the stage field becomes required and does not default to test anymore. The following job automatically defaults to the test stage:

my_job:
  script:
    - "true"

This job results in a YAML error complaining that stage must be defined:

my_job:
  script:
    - "true"
  needs: []

This fixes the issue by explicitly defining the implicit stage:

my_job:
  script:
    - "true"
  stage: test
  needs: []

Steps to reproduce

Use needs keyword without a stage directive.

Example Project

N/A

What is the current bug behavior?

The default stage is not used.

What is the expected correct behavior?

The default stage is used.

Relevant logs and/or screenshots

N/A

Output of checks

This bug happens on GitLab.com

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)