Use pendulum instead of datetime for a DAG's start_date

This aligns our DAGs with the Airflow example DAGs. See apache/airflow#21646.

dags/data_retention_delete_dag.py

@@ -8,10 +8,10 @@
 In CrateDB, tables for storing retention policies need to be created once manually.
 See the file setup/data_retention_schema.sql in this repository.
 """
-import datetime
 import json
 import logging
 from pathlib import Path
+import pendulum
 from airflow import DAG
 from airflow.providers.postgres.operators.postgres import PostgresOperator
 from airflow.providers.postgres.hooks.postgres import PostgresHook
@@ -62,7 +62,7 @@ def delete_partitions(ti):
 
 with DAG(
     dag_id="data-retention-delete-dag",
-    start_date=datetime.datetime(2021, 11, 19),
+    start_date=pendulum.datetime(2021, 11, 19, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag:

dags/data_retention_reallocate_dag.py

@@ -6,10 +6,10 @@
 In CrateDB, tables for storing retention policies need to be created once manually.
 See the file setup/data_retention_schema.sql in this repository.
 """
-import datetime
 import json
 import logging
 from pathlib import Path
+import pendulum
 from airflow import DAG
 from airflow.providers.postgres.operators.postgres import PostgresOperator
 from airflow.providers.postgres.hooks.postgres import PostgresHook
@@ -85,7 +85,7 @@ def reallocate_partitions(ti):
 
 with DAG(
     dag_id="data-retention-reallocate-dag",
-    start_date=datetime.datetime(2021, 11, 19),
+    start_date=pendulum.datetime(2021, 11, 19, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag:

dags/data_retention_snapshot_dag.py

@@ -6,10 +6,10 @@
 In CrateDB, tables for storing retention policies need to be created once manually.
 See the file setup/data_retention_schema.sql in this repository.
 """
-import datetime
 import json
 import logging
 from pathlib import Path
+import pendulum
 from airflow import DAG
 from airflow.providers.postgres.operators.postgres import PostgresOperator
 from airflow.providers.postgres.hooks.postgres import PostgresHook
@@ -77,7 +77,7 @@ def snapshot_partitions(ti):
 
 with DAG(
     dag_id="data-retention-snapshot-dag",
-    start_date=datetime.datetime(2022, 1, 31),
+    start_date=pendulum.datetime(2022, 1, 31, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag:

dags/financial_data_dag.py

@@ -11,6 +11,7 @@
 import math
 import json
 import logging
+import pendulum
 import requests
 from bs4 import BeautifulSoup
 import yfinance as yf
@@ -109,7 +110,7 @@ def format_and_insert_data_function(ti):
 
 with DAG(
     dag_id="financial_data_dag",
-    start_date=datetime.datetime(2022, 1, 10),
+    start_date=pendulum.datetime(2022, 1, 10, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag:

dags/nyc_taxi_dag.py

@@ -10,10 +10,9 @@
 You can retrieve the CREATE TABLE statements from the file setup/taxi-schema.sql
 in this repository.
 """
-import datetime
 import logging
-
 from pathlib import Path
+import pendulum
 from airflow import DAG
 from airflow.providers.postgres.operators.postgres import PostgresOperator
 from airflow.providers.postgres.hooks.postgres import PostgresHook
@@ -86,7 +85,7 @@ def process_new_files(ti):
 
 with DAG(
     dag_id="nyc-taxi",
-    start_date=datetime.datetime(2021, 11, 11),
+    start_date=pendulum.datetime(2021, 11, 11, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag:

dags/table_export_dag.py

@@ -3,9 +3,8 @@
 
 A detailed tutorial is available at https://community.crate.io/t/cratedb-and-apache-airflow-automating-data-export-to-s3/901
 """
-import datetime
 import os
-
+import pendulum
 from airflow import DAG
 from airflow.providers.postgres.operators.postgres import PostgresOperator
 from airflow.utils.task_group import TaskGroup
@@ -16,7 +15,7 @@
 
 with DAG(
     dag_id="cratedb_table_export",
-    start_date=datetime.datetime(2021, 11, 11),
+    start_date=pendulum.datetime(2021, 11, 11, tz="UTC"),
     schedule_interval="@daily",
     catchup=False,
 ) as dag: