Update peewee to 3.8.0

[pyup-bot]

This PR updates peewee from 3.7.1 to 3.8.0.

Changelog

3.8.0

**New features**

* Postgres `BinaryJSONField` now supports `has_key()`, `concat()` and
`remove()` methods (though remove may require pg10+).
* Add `python_value()` method to the SQL-function helper `fn`, to allow
specifying a custom function for mapping database values to Python values.

**Changes**

* Better support for UPDATE ... FROM queries, and more generally, more robust
support for UPDATE and RETURNING clauses. This means that the
`QualifiedNames` helper is no longer needed for certain types of queries.
* The `SqlCipherDatabase` no longer accepts a `kdf_iter` parameter. To
configure the various SQLCipher encryption settings, specify the setting
values as `pragmas` when initializing the database.
* Introspection will now, by default, only strip "_id" from introspected column
names if those columns are foreign-keys. See 1799 for discussion.
* Allow `UUIDField` and `BinaryUUIDField` to accept hexadecimal UUID strings as
well as raw binary UUID bytestrings (in addition to `UUID` instances, which
are already supported).
* Allow `ForeignKeyField` to be created without an index.
* Allow multiple calls to `cast()` to be chained (1795).
* Add logic to ensure foreign-key constraint names that exceed 64 characters
are truncated using the same logic as is currently in place for long indexes.
* `ManyToManyField` supports foreign-keys to fields other than primary-keys.
* When linked against SQLite 3.26 or newer, support `SQLITE_CONSTRAINT` to
designate invalid queries against virtual tables.
* SQL-generation changes to aid in supporting using queries within expressions
following the SELECT statement.

**Bugfixes**

* Fixed bug in `order_by_extend()`, thanks nhatHero.
* Fixed bug where the `DataSet` CSV import/export did not support non-ASCII
characters in Python 3.x.
* Fixed bug where `model_to_dict` would attempt to traverse explicitly disabled
foreign-key backrefs (1785).
* Fixed bug when attempting to migrate SQLite tables that have a field whose
column-name begins with "primary_".
* Fixed bug with inheriting deferred foreign-keys.

[View commits](https://github.com/coleifer/peewee/compare/3.7.1...3.8.0)

Links

• PyPI: https://pypi.org/project/peewee
• Changelog: https://pyup.io/changelogs/peewee/
• Repo: https://github.com/coleifer/peewee/

[coveralls]

Coverage remained the same at 83.873% when pulling abe06c3 on pyup-update-peewee-3.7.1-to-3.8.0 into f7ff8c6 on master.

[coveralls]

Coverage remained the same at 83.873% when pulling 1e38c1e on pyup-update-peewee-3.7.1-to-3.8.0 into e54ff61 on master.