Crate

- Core: Support `INSERT...VALUES` with multiple value sets by enabling
`supports_multivalues_insert` on the CrateDB dialect, it is used by pandas'
`method="multi"` option

- Core: Enable the `insertmanyvalues` feature, which lets you control
the batch size of `INSERT` operations using the `insertmanyvalues_page_size`
engine-, connection-, and statement-options.

- ORM: Remove support for the legacy `session.bulk_save_objects` API
on SQLAlchemy 2.0, in favor of the new `insertmanyvalues` feature. Performance
optimizations from `bulk_save()` have been made inherently part of `add_all()`.
Note: The legacy mode will still work on SQLAlchemy 1.x, while SQLAlchemy 2.x users
MUST switch to the new method now.

- Fixed SQLAlchemy 2.0 incompatibility with `CrateDialect.{has_schema,has_table}`

- Added deprecation warning about dropping support for SQLAlchemy 1.3 soon, it
is effectively EOL.

- Added support for SQLAlchemy 2.0. See also [What's New in SQLAlchemy 2.0]
and [SQLAlchemy 2.0 migration guide].

- Updated to geojson 3.0.0.

[SQLAlchemy 2.0 migration guide]: https://docs.sqlalchemy.org/en/20/changelog/migration_20.html
[What's New in SQLAlchemy 2.0]: https://docs.sqlalchemy.org/en/20/changelog/whatsnew_20.html

- Added support for `crate_index` and `nullable` attributes in
ORM column definitions.

- Added support for converting `TIMESTAMP` columns to timezone-aware
`datetime` objects, using the new `time_zone` keyword argument.

- Added a generic data type converter to the `Cursor` object, for converting
fetched data from CrateDB data types to Python data types.

- Fixed generating appropriate syntax for OFFSET/LIMIT clauses. It was possible
that SQL statement clauses like `LIMIT -1` could have been generated. Both
PostgreSQL and CrateDB only accept `LIMIT ALL` instead.

- Added support for ORM computed columns

- Improved `CrateDialect.get_pk_constraint` to be compatible
with breaking changes in CrateDB >=5.1.0.