Update responses to 0.26.0

[pyup-bot]

This PR updates responses from 0.25.7 to 0.26.0.

Changelog

0.26.0

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* When using `assert_all_requests_are_fired=True`, assertions about
unfired requests are now raised even when an exception occurs in the context manager or
decorated function. Previously, these assertions were suppressed when exceptions occurred.
This new behavior provides valuable debugging context about which mocked requests were
or weren't called.
* Consider the `Retry-After` header when handling retries

0.25.8

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* Fix bug where the content type is always recorded as either text/plain or application/json. See 770
* Allow asserts on add_callback() matches. See 727

Links

• PyPI: https://pypi.org/project/responses
• Changelog: https://data.safetycli.com/changelogs/responses/
• Repo: https://github.com/getsentry/responses