Spotipy

Added
- Added optional `encoder_cls` argument to `CacheFileHandler`, which overwrite default encoder for token before writing to disk
- Integration tests for searching multiple types in multiple markets (non-user endpoints)
- Publish to PyPI action

Fixed
- Fixed the regex for matching playlist URIs with the format spotify:user:USERNAME:playlist:PLAYLISTID.
- `search_markets` now factors the counts of all types in the `total` rather than just the first type ([534](https://github.com/spotipy-dev/spotipy/issues/534))

Removed

Added

- Add alternative module installation instruction to README
- Added Comment to README - Getting Started for user to add URI to app in Spotify Developer Dashboard.
- Added playlist_add_tracks.py to example folder

Changed

- Modified docstring for playlist_add_items() to accept "only URIs or URLs",
with intended deprecation for IDs in v3

Fixed

- Path traversal vulnerability that may lead to type confusion in URI handling code
- Update contributing.md

Added

- Integration tests via GHA (non-user endpoints)
- Unit tests for new releases, passing limit parameter with minimum and maximum values of 1 and 50
- Unit tests for categories, omitting country code to test global releases
- Added `CODE_OF_CONDUCT.md`

Fixed

- Incorrect `category_id` input for test_category
- Assertion value for `test_categories_limit_low` and `test_categories_limit_high`
- Pin Github Actions Runner to Ubuntu 20 for Py27
- Fixed potential error where `found` variable in `test_artist_related_artists` is undefined if for loop never evaluates to true
- Fixed false positive test `test_new_releases` which looks up the wrong property of the JSON response object and always evaluates to true

Added

- Added `market` parameter to `album` and `albums` to address ([753](https://github.com/plamere/spotipy/issues/753)
- Added `show_featured_artists.py` to `/examples`.
- Expanded contribution and license sections of the documentation.
- Added `FlaskSessionCacheHandler`, a cache handler that stores the token info in a flask session.
- Added Python 3.10 in GitHub Actions

Fixed

- Updated the documentation to specify ISO-639-1 language codes.
- Fix `AttributeError` for `text` attribute of the `Response` object
- Require redis v3 if python2.7 (fixes readthedocs)

Added

- Added `RedisCacheHandler`, a cache handler that stores the token info in Redis.
- Changed URI handling in `client.Spotify._get_id()` to remove qureies if provided by error.
- Added a new parameter to `RedisCacheHandler` to allow custom keys (instead of the default `token_info` key)
- Simplify check for existing token in `RedisCacheHandler`

Changed

- Removed Python 3.5 and added Python 3.9 in Github Action

Added

- Added `MemoryCacheHandler`, a cache handler that simply stores the token info in memory as an instance attribute of this class.
- If a network request returns an error status code but the response body cannot be decoded into JSON, then fall back on decoding the body into a string.
- Added `DjangoSessionCacheHandler`, a cache handler that stores the token in the session framework provided by Django. Web apps using spotipy with Django can directly use this for cache handling.

Fixed

- Fixed a bug in `CacheFileHandler.__init__`: The documentation says that the username will be retrieved from the environment, but it wasn't.
- Fixed a bug in the initializers for the auth managers that produced a spurious warning message if you provide a cache handler and you set a value for the "SPOTIPY_CLIENT_USERNAME" environment variable.
- Use generated MIT license and fix license type in `pip show`