django.core.exceptions.ImproperlyConfigured: mysqlclient 1.3.13 or newer is required; you have 0....

Django2.2x, Python3.6在migrate时出现以下问题：
django.core.exceptions.ImproperlyConfigured: mysqlclient 1.3.13 or newer is required; you have 0.9.3.

网上流行注释掉两行，还是不行，另外总觉得去改设置文件也不是个好的习惯，继续找路，发现：

As per this pull request, The problem is not only the version number of mysqlclient. As per this ticket #30380, there may be many places in django where support for PyMySQL could be broken, and Django will not fix them(probably). Also, as per tickets #12500, #22391, Django does not support PyMySQL officially.

所以用mysqlclient取代pymysql:

1. 删除项目__init__.py里pymysql的设置
2. pip install mysqlclient
3. 搞定！

进一步可以参考这里：https://stackoverflow.com/questions/55472739/have-a-problem-using-django-2-2-with-pymysql