Bump attrs from 18.2.0 to 19.1.0

[dependabot-preview]

Bumps attrs from 18.2.0 to 19.1.0.

Changelog

Sourced from attrs's changelog.

19.1.0 (2019-03-03)

Backward-incompatible Changes

• Fixed a bug where deserialized objects with cache_hash=True could have incorrect hash code values. This change breaks classes with cache_hash=True when a custom __setstate__ is present. An exception will be thrown when applying the attrs annotation to such a class. This limitation is tracked in issue #494. #482

Changes

• Add is_callable, deep_iterable, and deep_mapping validators.

  • is_callable: validates that a value is callable
  • deep_iterable: Allows recursion down into an iterable, applying another validator to every member in the iterable as well as applying an optional validator to the iterable itself.
  • deep_mapping: Allows recursion down into the items in a mapping object, applying a key validator and a value validator to the key and value in every item. Also applies an optional validator to the mapping object itself.

  You can find them in the attr.validators package. #425

• Fixed stub files to prevent errors raised by mypy's disallow_any_generics = True option. #443

• Attributes with init=False now can follow after kw_only=True attributes. #450

• attrs now has first class support for defining exception classes.

  If you define a class using [@​attr.s](https://github.com/attr.s)(auto_exc=True) and subclass an exception, the class will behave like a well-behaved exception class including an appropriate __str__ method, and all attributes additionally available in an args attribute. #500

• Clarified documentation for hashing to warn that hashable objects should be deeply immutable (in their usage, even if this is not enforced). #503

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Commits

• 0356f06 Prepare 19.1.0
• 8b83ef7 Brandon got TLS now!
• 0f453c6 Add a pointless line to newsfragment to trick towncrier
• d74434f Ignore pip-wheel-metadata
• 4b88f92 Remove _add_init
• 25a98cb Implement first class exception support (#500)
• a35d8fb fix and simplify docs CI
• aa9f62f Use 3.7 for RTD
• 4de9481 Exclude test_annotations from pypy3
• 1fada3d Be consistent in calling slotted classes slotted
• Additional commits viewable in compare view

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[dependabot-preview]

Superseded by #165.