Whenever

------------------

**Breaking changes**

- 🥒 Change pickle format so that backwards-compatible unpickling is possible
in the future.

**Added**

- 🔨 Added ``strptime()`` to ``UTCDateTime``, ``OffsetDateTime`` and
``NaiveDateTime``.
- 📋 Added ``rfc2822()``/``from_rfc2822()`` to ``UTCDateTime``,
``OffsetDateTime`` and ``NaiveDateTime``.
- ⚙️ Added ``rfc3339()``/``from_rfc3339()`` to ``UTCDateTime`` and ``OffsetDateTime``

------------------

- added ``days()`` timedelta alias
- Improvements to README, other docs

------------------

**Breaking changes**

- 📐Disambiguation of local datetimes is now consistent with zoned datetimes,
and is also run on ``replace()``.
- 👌Renamed:

- ``from_str`` → ``from_canonical_str``
- ``to_utc/offset/zoned/local`` → ``as_utc/offset/zoned/local``.
- ``ZonedDateTime.zone`` → ``ZonedDateTime.tz``

**Added**

- ⚖️ Support comparison between all aware datetimes
- 🧮Support subtraction between all aware datetimes
- 🍩 Convenience methods for converting between aware/naive
- 💪 More robust handling of zoned/local edge cases

**Docs**

- Cleaned up API reference
- Added high-level overview

------------------

- 🚀 Implement ``OffsetDateTime``, ``ZonedDateTime`` and ``LocalDateTime``

------------------

- 🐍 Revert to pure Python implementation, as Rust extension disadvantages
outweigh its advantages
- ☀️ Implement ``NaiveDateTime``

------------------

- 🌐 Implement basic ``UTCDateTime``