ref: upgrade isort to work around poetry breakage

[asottile-sentry]

https://github.com/python-poetry/poetry-core/pull/542

Committed via https://github.com/asottile/all-repos

[codecov[bot]]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage :thumbsup:

Coverage data is based on head (3f029ae) compared to base (48d8af9). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #620 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 9 9 Lines 2801 2801 ========================================= Hits 2801 2801 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=getsentry). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=getsentry)

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