Support updating pull request status instead of only commits

[triztian]

As the title states the URL in step.sh is hardcoded to a commits path. It'd be nice if it would be able to support urls like the following:

https://$devops_user:$devops_pat@dev.azure.com/${devops_organization}/${devops_project}/_apis/git/repositories/${devops_repository_id}/${devops_object_type}/${devops_object_id}/statuses?api-version=5.1

The inputs could be updated to the following:

- devops_object_type: commit
  opts:
    description: |
      The type of object that is being updated.

      Possible values are `commits`, `pullRequest`
    is_expand: true
    is_required: false
    title: DevOps Object Type
    value_options:
    - commits
    - pullRequest