The database provider attempted to register an implementation of the 'IRelationalTypeMappingSource' service.
EFCore连接数据库遇到的问题：
The database provider attempted to register an implementation of the 'IRelationalTypeMappingSource' service.
解决办法：
Microsoft.EntityFrameworkCore 5.0.1版本 改为 3.1.10版本
测试：
