docs(airflow): update badge (#693)

* Drop python 3.8 support and update badge

Signed-off-by: Nok Lam Chan <nok.lam.chan@quantumblack.com>

* Update pyproject.toml

Signed-off-by: Nok Lam Chan <nok.lam.chan@quantumblack.com>

* Update pyproject.toml

Signed-off-by: Nok Lam Chan <nok.lam.chan@quantumblack.com>

* Update README.md

Signed-off-by: Nok Lam Chan <nok.lam.chan@quantumblack.com>

---------

Signed-off-by: Nok Lam Chan <nok.lam.chan@quantumblack.com>

Author: noklam

kedro-airflow/README.md

@@ -1,7 +1,7 @@
 # Kedro-Airflow
 
 [![License](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
-[![Python Version](https://img.shields.io/badge/python-3.8%20%7C%203.9%20%7C%203.10%20%7C%203.11-blue.svg)](https://pypi.org/project/kedro-airflow/)
+[![Python Version](https://img.shields.io/badge/python-3.8%20%7C%203.9%20%7C%203.10%20%7C%203.11%20%7C%203.12-blue.svg)](https://pypi.org/project/kedro-airflow/)
 [![PyPI Version](https://badge.fury.io/py/kedro-airflow.svg)](https://pypi.org/project/kedro-airflow/)
 [![Code Style: Black](https://img.shields.io/badge/code%20style-black-black.svg)](https://github.com/ambv/black)