Support PostgreSQL Table Inhertiance

### Things to check first

- [X] I have searched the existing issues and didn't find my bug already reported there

- [X] I have checked that my bug is still present in the latest release

### Sqlacodegen version

3.0.0rc5

### SQLAlchemy version

2.0.29

### RDBMS vendor

PostgreSQL

### What happened?

When using sqlacodegen to generate ORM classes from an existing database schema, the child table ORM classes that inherit from base tables are not created. This issue occurs when there are tables using SQLAlchemy inheritance.

Is there any way to codegen child tables?

### Database schema for reproducing the bug

Up migrateion to reproduce is like below.

```sql
create schema "test";

CREATE TABLE "test"."base" ("base" integer NOT NULL, PRIMARY KEY ("base") );COMMENT ON TABLE "test"."base" IS E'base';

CREATE TABLE test.sub (
sub_data integer
) INHERITS (test.base);

```

Generated code.
```py
# Using geoalchemy2 0.14.7
from sqlalchemy import Column, Integer, PrimaryKeyConstraint, Table
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column

class Base(DeclarativeBase):
pass

class Base(Base):
__tablename__ = 'base'
__table_args__ = (
PrimaryKeyConstraint('base', name='base_pkey'),
{'comment': 'base', 'schema': 'test'}
)

base: Mapped[int] = mapped_column(Integer, primary_key=True)

t_sub = Table(
'sub', Base.metadata,
Column('base', Integer, nullable=False),
Column('sub_data', Integer),
schema='test'
)

```