Adding name: changes build jobs

That’s finally saved my day. I was revisiting Overriding default job from os matrix to understand how to exclude default job, and it appeared that it was not a default job, but an explicit job added by this typo.

  include:
    - stage: lint
    - python: 3.6
      env: TOXENV=bandit

https://travis-ci.org/release-monitoring/anitya/builds/566916684/config

To avoid these mistakes, it would help to support indented syntax for stages that could also disable all default jobs.

stages:
  - lint
    - script: one
  - test
    - script: two
    - script: three
      env: special
  - docker
    - script: docker