Update yapf to 0.21.0

[pyup-bot]

This PR updates yapf from 0.18.0 to 0.21.0.

Changelog

0.21.0

Added
- Introduce a new option of formatting multiline literals. Add
`SPLIT_BEFORE_CLOSING_BRACKET` knob to control whether closing bracket should
get their own line.
- Add 'BLANK_LINES_AROUND_TOP_LEVEL_DEFINITION' knob to control the number
of blank lines between top-level function and class definitions.
- Added `CONTINUATION_ALIGN_STYLE` knob to choose continuation alignment style
when `USE_TABS` is enabled.
Fixed
- Don't split ellipses.

0.20.2

Changed
- Improve the speed at which files are excluded by ignoring them earlier.
- Allow dictionaries to stay on a single line if they only have one entry
Fixed
- Use tabs when constructing a continuation line when `USE_TABS` is enabled.
- A dictionary entry may not end in a colon, but may be an "unpacking"
operation: `**foo`. Take that into accound and don't split after the
unpacking operator.

0.20.1

Fixed
- Don't treat 'None' as a keyword if calling a function on it, like '__ne__()'.
- use_tabs=True always uses a single tab per indentation level; spaces are
used for aligning vertically after that.
- Relax the split of a paren at the end of an if statement. With
`dedent_closing_brackets` option requires that it be able to split there.

0.20.0

Added
- Improve splitting of comprehensions and generators. Add
`SPLIT_PENALTY_COMPREHENSION` knob to control preference for keeping
comprehensions on a single line and `SPLIT_COMPLEX_COMPREHENSION` to enable
splitting each clause of complex comprehensions onto its own line.
Changed
- Take into account a named function argument when determining if we should
split before the first argument in a function call.
- Split before the first argument in a function call if the arguments contain a
dictionary that doesn't fit on a single line.
- Improve splitting of elements in a tuple. We want to split if there's a
function call in the tuple that doesn't fit on the line.
Fixed
- Enforce spaces between ellipses and keywords.
- When calculating the split penalty for a "trailer", process the child nodes
afterwards because their penalties may change. For example if a list
comprehension is an argument.
- Don't enforce a split before a comment after the opening of a container if it
doesn't it on the current line. We try hard not to move such comments around.
- Use a TextIOWrapper when reading from stdin in Python3. This is necessary for
some encodings, like cp936, used on Windows.
- Remove the penalty for a split before the first argument in a function call
where the only argument is a generator expression.

0.19.0

Added
- Added `SPLIT_BEFORE_EXPRESSION_AFTER_OPENING_PAREN` that enforces a split
after the opening paren of an expression that's surrounded by parens.
Changed
- Split before the ending bracket of a comma-terminated tuple / argument list
if it's not a single element tuple / arg list.
Fixed
- Prefer to split after a comma in an argument list rather than in the middle
of an argument.
- A non-multiline string may have newlines if it contains continuation markers
itself. Don't add a newline after the string when retaining the vertical
space.
- Take into account the "async" keyword when determining if we must split
before the first argument.
- Increase affinity for "atom" arguments in function calls. This helps prevent
lists from being separated when they don't need to be.
- Don't place a dictionary argument on its own line if it's the last argument
in the function call where that function is part of a builder-style call.
- Append the "var arg" type to a star in a star_expr.

Links

• PyPI: https://pypi.org/project/yapf
• Changelog: https://pyup.io/changelogs/yapf/