feat: fix README badges (#7)

Author: Chimou0

README.md

@@ -1,12 +1,12 @@
 SQLAlchemy Adapter for PyCasbin 
 ====
 
-[![GitHub Actions](https://github.com/officialpycasbin/sqlalchemy-adapter/workflows/build/badge.svg?branch=master)](https://github.com/officialpycasbin/sqlalchemy-adapter/actions)
+[![build](https://github.com/officialpycasbin/sqlalchemy-adapter/actions/workflows/build.yml/badge.svg)](https://github.com/officialpycasbin/sqlalchemy-adapter/actions/workflows/build.yml)
 [![Coverage Status](https://coveralls.io/repos/github/officialpycasbin/sqlalchemy-adapter/badge.svg)](https://coveralls.io/github/officialpycasbin/sqlalchemy-adapter)
 [![Version](https://img.shields.io/pypi/v/sqlalchemy-adapter.svg)](https://pypi.org/project/sqlalchemy-adapter/)
 [![PyPI - Wheel](https://img.shields.io/pypi/wheel/sqlalchemy-adapter.svg)](https://pypi.org/project/sqlalchemy-adapter/)
 [![Pyversions](https://img.shields.io/pypi/pyversions/sqlalchemy-adapter.svg)](https://pypi.org/project/sqlalchemy-adapter/)
-[![Download](https://img.shields.io/pypi/dm/sqlalchemy-adapter.svg)](https://pypi.org/project/sqlalchemy-adapter/)
+[![Download](https://static.pepy.tech/badge/sqlalchemy-adapter)](https://pypi.org/project/sqlalchemy-adapter/)
 [![License](https://img.shields.io/pypi/l/sqlalchemy-adapter.svg)](https://pypi.org/project/sqlalchemy-adapter/)
 
 SQLAlchemy Adapter is the [SQLAlchemy](https://www.sqlalchemy.org) adapter for [PyCasbin](https://github.com/casbin/pycasbin). With this library, Casbin can load policy from SQLAlchemy supported database or save policy to it.