Update raven to 6.1.0

[pyup-bot]

There's a new version of raven available.
You are currently using 5.27.0. I have updated it to 6.1.0

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

Changelog

6.1.0

---

• Support both string and class values for ignore_exceptions parameters.
  Class values also support child exceptions.
• Ensure consistent fingerprint for SoftTimeLimitExceeded exceptions
• Add sample_rate configuration
• fix registration of hooks for Django

6.0.0

---

• Strip whitespace from DSNs automatically.
• Add last_event_id accessor to Client.
• Do not require sys.argv to be available any more.
• Tags defined on a logging handler will now be merged with individual log record's tags.
• Added explicit support for multidicts in the django client.
• Refactored transports to support multiple URLs. This might affect
  you if you have custom subclasses of those. The main change is that
  the URL parameter moved from the constructor into the send method.
• Corrected an issue with recursive route resolvers which commonly
  affected things like django-tastyepie.
• Corrected an issue where Django's HTTP request was not always available
  within events.

5.32.0

---

• Made raven python breadcrumb patches work when librato monkey
  patches logging.

5.31.0

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• Improved fix for the Django middleware regression.

5.30.0

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• Keep the original type for the django middleware settings if we
  change them.

5.29.0

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• Added register_logging_handler.
• Removed bad mixin from django's WSGI middleware
• Removed "support for extracing data from rest_framework" because
  this broke code.

5.28.0

---

• Corrected an issue that caused close() on WSGI iterables to not be
  correctly called.
• Fixes the new Django 1.10 MIDDLEWARE_CLASSES warning.

5.27.1

---

• Bugfix for transaction based culprits.

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

Happy merging! 🤖

[mention-bot]

@pyup-bot, thanks for your PR! By analyzing the history of the files in this pull request, we identified @ad-m and @requires to be potential reviewers.

[pyup-bot]

Closing this in favor of #279