Alembic automatic migration scripts with compare_type=True fails for Float types

[AntonFriberg]

Describe the bug

If you enable Alembic's optional detection of column type changes (https://alembic.sqlalchemy.org/en/latest/autogenerate.html#what-does-autogenerate-detect-and-what-does-it-not-detect) it would generate a change that changes a sqlalchemy.sql.sqltypes.FLOAT column into a clickhouse_sqlalchemy.types.common.Float64 column despite the model specifying a clickhouse_sqlalchemy.types.common.Float64 and the table having a Float64 type.

Expected behavior
The generated alembic migration should not contain changes of FLOAT into Float64 if the type is Float64 already.

Versions

• Version of package with the problem.
• Current master clickhouse-sqlalchemy @ git+https://github.com/xzkostyan/clickhouse-sqlalchemy@c69984feb7b210553969b21505f4495ffb5a4b77

I believe I have found the source of the problem in https://github.com/xzkostyan/clickhouse-sqlalchemy/blob/master/clickhouse_sqlalchemy/drivers/base.py#L40 . The inconsistency with the type converter definitions seems to cause this. I will upload a PR which solves my problem and removes the inconsistency.