ModelGenerator's output raises NameError for decimal fields

[rgson]

Describe the bug
Code generated by the ModelGenerator for schemas containing a decimal logical type field cannot run due to a missing import.

To Reproduce

import dataclasses_avroschema

schema = {
    "type": "record",
    "name": "demo",
    "fields": [
        {
            "name": "foo",
            "type": {
                "type": "bytes",
                "logicalType": "decimal",
                "precision": 10,
                "scale": 3
            }
        }
    ]
}
code = dataclasses_avroschema.ModelGenerator().render(schema=schema)

with open("/tmp/generated_code.py", "w") as f:
    print(code, file=f)

python3 /tmp/generated_code.py

Traceback (most recent call last):
  File "/tmp/generated_code.py", line 7, in <module>
    class Demo(AvroModel):
  File "/tmp/generated_code.py", line 8, in Demo
    foo: decimal.Decimal = types.Decimal(scale=3, precision=10)
                           ^^^^^
NameError: name 'types' is not defined. Did you mean: 'type'?

Expected behavior
Loadable code without the NameError.

[marcosschroh]

Probably it is missing an import on the top. I will check it