**Description**

Don't mark dag as `failed` when `UNSTABLE` status received from Jenkins.
It can be done by adding `allow_unstable: bool` or `success_status_values: list` parameter to `JenkinsJobTriggerOperator.__init__`. For now `SUCCESS` status is hardcoded, any other lead to fail.

**Use case / motivation**

I want to restart a job (`retries` parameter) only if I get `FAILED` status. `UNSTABLE` is okay for me and it's no need to restart.

**Are you willing to submit a PR?**

Yes

**Related Issues**

No

airflow/providers/jenkins/operators/jenkins_job_trigger.py
"""
    Trigger a Jenkins Job and monitor it's execution.
    This operator depend on python-jenkins library,
    version >= 0.4.15 to communicate with jenkins server.
    You'll also need to configure a Jenkins connection in the connections screen.
    :param jenkins_connection_id: The jenkins connection to use for this job
    :type jenkins_connection_id: str
    :param job_name: The name of the job to trigger
    :type job_name: str
    :param parameters: The parameters block provided to jenkins for use in
        the API call when triggering a build. (templated)
    :type parameters: str, Dict, or List
    :param sleep_time: How long will the operator sleep between each status
        request for the job (min 1, default 10)
    :type sleep_time: int
    :param max_try_before_job_appears: The maximum number of requests to make
        while waiting for the job to appears on jenkins server (default 10)
    :type max_try_before_job_appears: int
    """
    template_fields = ('parameters',)
    template_ext = ('.json',)
    ui_color = '#f9ec86'
    @apply_defaults
    def __init__(