Clearly document no breaking change for 2.1.2 and 2.1.3 (#17706)

Similar to apache/airflow#6240

GitOrigin-RevId: 87e64fad5b05dd4626c0b936e738586adc1600ae

UPDATING.md

@@ -27,6 +27,8 @@ assists users migrating to a new version.
 **Table of contents**
 
 - [Main](#main)
+- [Airflow 2.1.3](#airflow-213)
+- [Airflow 2.1.2](#airflow-212)
 - [Airflow 2.1.1](#airflow-211)
 - [Airflow 2.1.0](#airflow-210)
 - [Airflow 2.0.2](#airflow-202)
@@ -184,6 +186,14 @@ Now that the DAG parser syncs DAG permissions there is no longer a need for manu
 
 In addition, the `/refresh` and `/refresh_all` webserver endpoints have also been removed.
 
+## Airflow 2.1.3
+
+No breaking changes.
+
+## Airflow 2.1.2
+
+No breaking changes.
+
 ## Airflow 2.1.1
 
 ### `activate_dag_runs` argument of the function `clear_task_instances` is replaced with `dag_run_state`