**Description**

It would be great having a option to abort a DAG Runs through the REST API.

**Use case / motivation**

The proposed input params would be:
 - DAG_ID
 - DAG_RUN_ID

The DAG Run should abort all its tasks running and mark them as "failed".

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

**Related Issues**


tests/api_connexion/endpoints/test_dag_run_endpoint.py
'external_trigger': True,
                    'start_date': self.default_time,
                    'conf': {},
                },
            ],
            "total_entries": 2,
        }
    @parameterized.expand(
        [
            (
                {"dag_ids": ["TEST_DAG_ID"], "page_offset": -1},
                "-1 is less than the minimum of 0 - 'page_offset'",
            ),
            ({"dag_ids": ["TEST_DAG_ID"], "page_limit": 0}, "0 is less than the minimum of 1 - 'page_limit'"),
            ({"dag_ids": "TEST_DAG_ID"}, "'TEST_DAG_ID' is not of type 'array' - 'dag_ids'"),
            ({"start_date_gte": "2020-06-12T18"}, "{'start_date_gte': ['Not a valid datetime.']}"),
        ]
    )
    def test_payload_validation(self, payload, error):
        self._create_test_dag_run()
        response = self.client.post(
            "api/v1/dags/~/dagRuns/list", json=payload, environ_overrides={'REMOTE_USER': "test"}
        )
        assert response.status_code == 400
        assert error == response.json.get("detail")
    def test_should_raises_401_unauthenticated(self):
        self._create_test_dag_run()
        response = self.client.post("api/v1/dags/~/dagRuns/list", json={"dag_ids": ["TEST_DAG_ID"]})
        assert_401(response)
class TestGetDagRunBatchPagination(TestDagRunEndpoint):