Local Executor is used by default for MySQL/Postgres breeze (#11792)

scripts/ci/docker-compose/backend-mysql.yml

@@ -23,6 +23,7 @@ services:
       - AIRFLOW__CORE__SQL_ALCHEMY_CONN=mysql://root@mysql/airflow?charset=utf8mb4
       - AIRFLOW__CORE__SQL_ENGINE_COLLATION_FOR_IDS=utf8mb3_general_ci
       - AIRFLOW__CELERY__RESULT_BACKEND=db+mysql://root@mysql/airflow?charset=utf8mb4
+      - AIRFLOW__CORE__EXECUTOR=LocalExecutor
     depends_on:
       - mysql
   mysql:

scripts/ci/docker-compose/backend-postgres.yml

@@ -22,6 +22,7 @@ services:
       - BACKEND=postgres
       - AIRFLOW__CORE__SQL_ALCHEMY_CONN=postgresql+psycopg2://postgres:airflow@postgres/airflow
       - AIRFLOW__CELERY__RESULT_BACKEND=db+postgresql://postgres:airflow@postgres/airflow
+      - AIRFLOW__CORE__EXECUTOR=LocalExecutor
     depends_on:
       - postgres
   postgres: