Ytmusicapi

Fixes 🐞
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- `search`: fixed error if result thumbnail is missing
- `get_watch_playlist`: fixed results if only videoid is provided. Only a single result was being returned, now the video's radio playlist parameter is being passed by default
- `get_library_playlists`: playlist `count` variable is now returned

Changes 🛠
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- added a request timeout of 30s to the default session. Refer to the documentation for how to adjust this timeout: https://ytmusicapi.readthedocs.io/en/latest/reference.html#ytmusicapi.YTMusic.__init__
- `search`: added `category` property to search results, which indicates the shelf that the result is a part of. Can be used to identify "top result" type search results

Fixes 🐞
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- some housekeeping, removed some deprecated code

Fixes 🐞
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- fixed a parsing bug for default search (no filter, no scope) introduced in 0.19.0

Fixes 🐞
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- improved Python compatibility (3.5 no longer supported due to end-of-life, 3.9 now works without issues)
- `get_charts`: fixed some parsing issues

Fixes 🐞
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- `get_album`, `get_library_upload_album`: fixed crash caused by `audioPlaylistId` returned in different JSON keys to different users

Features ✨
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- `search`: Support the new **library search** that was rolled out globally this week. For this purpose, a new `scope` parameter was introduced for `search`. It can take `uploads` or `library` values depending on the alternative search scope intended. Consequentially, `uploads` is no longer passed using the `filter` argument. The `filter` argument can be used without a scope (global YouTube Music catalogue search, as previously), or with the new library search. All existing filters work with the library search except the videos filter, as you cannot add videos to your library (only to liked playlist)
- `get_charts`: get latest chart data from YouTube Music. This further contributes to ytmusicapi's implementation of the Explore tab in YouTube Music, after the moods and genres implementation in 0.18.0. The function retrieves all data shown on the `/charts` page and takes a country code as parameter, or `ZZ` for global charts.

Changes ⚒
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- **BREAKING**: to improve consistency across the project, the key `artists` is now used whenever a list of artists with (name,id) dictionary is provided (instead of `artist`). This affects `get_album`, `get_library_upload_songs`, `get_library_upload_album`,`get_library_upload_artist`. See 215

Fixes 🐞
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- `get_library_upload_albums`: a key in the data structure was changed in a recent YouTube update, the function should now work again without issue