When deleting a field with unqiue=True it will raise KeyError #364
Description
Describe the bug
When deleting a field with unqiue=True it will raise KeyError.
To Reproduce
version：
mysql8.0，tortoise-orm branch is develop（version 905daaa53928622b53454f65fd629690a7e5491f），aerich branch is dev（version 15d5612）
Steps to Reproduction：
1.This is my model
class Tasks(Model):
"""任务表"""
id = fields.IntField(pk=True)
name = fields.CharField(max_length=100, unique=True, description="任务名称")
status = fields.IntEnumField(enum_type=TaskStatus, description="任务状态")
class Meta:
table = "tb_tasks"
2.Init db
aerich init -t utils.config.TORTOISE_CONFIG
aerich init-db
3.Delete the name field of the model from step 2
class Tasks(Model):
"""任务表"""
id = fields.IntField(pk=True)
status = fields.IntEnumField(enum_type=TaskStatus, description="任务状态")
class Meta:
table = "tb_tasks"
4.Migrate and upgrade
aerich migrate
aerich upgrade
5.It will raise a exception
KeyError: 'name'