Mir.anidb

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Updated dependencies.

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Updated dependencies.

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Updated dependencies.

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Removed
^^^^^^^

- Removed async API. It's not very useful and adds maintenance hassle and dependencies.

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Fixed
^^^^^

- Async APIs now correctly release client responses.

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Added
^^^^^

- The titles API is now `request_titles` and `async_request_titles`,
the same as the anime API.
- Added `get_main_title`.

Deprecated
^^^^^^^^^^

- `CachedTitlesGetter` and all related classes and functions are
deprecated. This logic should be implemented by the client.
Furthermore, the way it is implemented in `mir.anidb` is
unnecessarily complex.