Cannot cast type jsonb to character varying[] - Django

Question

I have django model with field

locations = JSONField(default=list, blank=True)

I want to alter field type to ArrayField using:

locations = ArrayField(CharField(max_length=100))

django makemigrations created migration file as:

operations = [
    migrations.AlterField(
        model_name='Employee',
        name='locations',
        field=django.contrib.postgres.fields.ArrayField(base_field=models.CharField(max_length=100), size=None),
    ),
]

But while running migration it throws error:

django.db.utils.ProgrammingError: cannot cast type jsonb to character varying[]

LINE 1: ... "locations" TYPE varchar(100)[] USING "locations"::varchar(...

What is the correct way of altering jsonb list field to arrayfield and how to typecast jsonb to arrayfield while running migration ?