Xocto

- Add `ranges.date_range_for_midnight_range` [178] (https://github.com/octoenergy/xocto/pull/178)
- Add `FiniteDatetimeRange.localize` [178] (https://github.com/octoenergy/xocto/pull/178)

- Add optional `timezone` parameter to datetime-based range fields [174] (https://github.com/octoenergy/xocto/pull/174)

- [Breaking] Use parameter object for passing options to `pact_service`.
Rename parameter `pact_version` to `consumer_version`.
[166](https://github.com/octoenergy/xocto/pull/166)
- Fix bug with `list_files` method in `S3SubdirectoryFileStore` [171] (https://github.com/octoenergy/xocto/pull/171)

- Add `ranges.iterate_over_months` function [163](https://github.com/octoenergy/xocto/pull/163)

- Implements `__copy__` and `__deepcopy__` on Range types [160](https://github.com/octoenergy/xocto/pull/160/)

- [Breaking] Range types are now (mostly) immutable [142](https://github.com/octoenergy/xocto/pull/142)
- start, end, and bounds can no longer be modified after creation
- [Breaking] The `types` module is now split into a package containing `types.generic` and `types.django` [144](https://github.com/octoenergy/xocto/pull/144)
- `xocto.numbers` and `xocto.ranges` can now be imported without configuring Django
- Postgres range database fields now allow querying by a single value [150](https://github.com/octoenergy/xocto/pull/150)
- `Storage.fetch_file` now supports fetching a range [154](https://github.com/octoenergy/xocto/pull/154/)
- Enables `FiniteDatetimeRange` to be unioned with more than two ranges [155](https://github.com/octoenergy/xocto/pull/155)