Apache Airflow 2.6.1

## Significant Changes ## Clarifications of the external Health Check mechanism and using ``Job`` classes (#31277). In the past SchedulerJob and other ``*Job`` classes are known to have been used to perform external health checks for Airflow components. Those are, however, Airflow DB ORM related classes. The DB models and database structure of Airflow are considered as internal implementation detail, following `public interface <https://airflow.apache.org/docs/apache-airflow/stable/public-airflow-interface.html>`_). Therefore, they should not be used for external health checks. Instead, you should use the ``airflow jobs check`` CLI command (introduced in Airflow 2.1) for that purpose. ## Bug Fixes - Fix calculation of health check threshold for SchedulerJob (#31277) - Fix timestamp parse failure for k8s executor pod tailing (#31175) - Make sure that DAG processor job row has filled value in ``job_type`` column (#31182) - Fix section name reference for ``api_client_retry_configuration`` (#31174) - Ensure the KPO runs pod mutation hooks correctly (#31173) - Remove worrying log message about redaction from the OpenLineage plugin (#31149) - Move ``interleave_timestamp_parser`` config to the logging section (#31102) - Ensure that we check worker for served logs if no local or remote logs found (#31101) - Fix ``MappedTaskGroup`` import in taskinstance file (#31100) - Format DagBag.dagbag_report() Output (#31095) - Mask task attribute on task detail view (#31125) - Fix template error when iterating None value and fix params documentation (#31078) - Fix ``apache-hive`` extra so it installs the correct package (#31068) - Fix issue with zip files in DAGs folder when pre-importing Airflow modules (#31061) - Move TaskInstanceKey to a separate file to fix circular import (#31033, #31204) - Fix deleting DagRuns and TaskInstances that have a note (#30987) - Fix ``airflow providers get`` command output (#30978) - Fix Pool schema in the OpenAPI spec (#30973) - Add support for dynamic tasks with template fields that contain ``pandas.DataFrame`` (#30943) - Use the Task Group explicitly passed to 'partial' if any (#30933) - Fix ``order_by`` request in list DAG rest api (#30926) - Include node height/width in center-on-task logic (#30924) - Remove print from dag trigger command (#30921) - Improve task group UI in new graph (#30918) - Fix mapped states in grid view (#30916) - Fix problem with displaying graph (#30765) - Fix backfill KeyError when try_number out of sync (#30653) - Re-enable clear and setting state in the TaskInstance UI (#30415) - Prevent DagRun's ``state`` and ``start_date`` from being reset when clearing a task in a running DagRun (#30125) ## Misc/Internal - Upper bind dask until they solve a side effect in their test suite (#31259) - Show task instances affected by clearing in a table (#30633) - Fix missing models in API documentation (#31021) ## Doc only changes - Improve description of the ``dag_processing.processes`` metric (#30891) - Improve Quick Start instructions (#30820) - Add section about missing task logs to the FAQ (#30717) - Mount the ``config`` directory in docker compose (#30662) - Update ``version_added`` config field for ``might_contain_dag`` and ``metrics_allow_list`` (#30969)