Update isort to 4.2.15

[pyup-bot]

There's a new version of isort available.
You are currently using 4.2.5. I have updated it to 4.2.15

These links might come in handy: PyPI | Changelog | Repo

Changelog

4.2.15

IMPORTANT NOTE: This will be the last release with Python 2.6 support, subsequent releases will be 2.7+ only

• Fixed certain one line imports not being successfully wrapped

4.2.14

• Fixed 559 & 565: Added missing standard library imports

4.2.13

• Fixed 553: Check only and --diff now work together again

4.2.12

• Fixed wheel distribution bug

4.2.11

• Fixed 546: Can't select y/n/c after latest update
• Fixed 545: Incorrectly moves future imports above encoding comments

4.2.9

• Fixed 428: Check only modifies sorting
• Fixed 540: Not correctly identifying stdlib modules

4.2.8

• Added --virtual-env switch command line option
• Added --enforce-whitespace option to go along with --check-only for more exact checks (issue 423)
• Fixed imports with a tailing '&Update psycopg2 to 2.7.1 #39; and no space in-between getting removed (issue 425)
• Fixed issue 299: long lines occasionally not wrapped
• Fixed issue 432: No longer add import inside class when class starts at top of file after encoding comment
• Fixed issue 440: Added missing --use-parentheses option to command line tool and documentation
• Fixed issue 496: import* imports now get successfully identified and reformatted instead of deleted
• Fixed issue 491: Non ending parentheses withing single line comments no longer cause formatting issues
• Fixed issue 471: Imports that wrap the maximum line length and contain comments on the last line are no longer rendered incorrectly
• Fixed issue 436: Force sort within section no longer rearranges comments
• Fixed issue 473: Force_to_top and force_sort_within_sections now work together
• Fixed issue 484 & 472: Consistent output with imports of same spelling but different case
• Fixed issue 433: No longer incorrectly add an extra new-line when comment between imports and function definition
• Fixed issue 419: Path specification for skipped paths is not Unix/Windows inter-operable.
  Breaking Changes:
  • Fixed issue 511: All command line options with an underscore, have had the underscore replaced with a dash for consistency. This effects: multi-line, add-import, remove-import, force-adds, --force-single-line-imports, and length-sort.
  • Replaced the --enforce-whitespace option with --ignore-whitespace to restore original behavior of strict whitespace by default

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖

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