- update to 0.21.0:
* Add `threading.Lock()` to allow `responses` working with `threading` module.
* Add `urllib3` `Retry` mechanism. See #135
* Removed internal `_cookies_from_headers` function
* Now `add`, `upsert`, `replace` methods return registered response.
`remove` method returns list of removed responses.
* Added null value support in `urlencoded_params_matcher` via `allow_blank` keyword argument
* Added strict version of decorator. Now you can apply `@responses.activate(assert_all_requests_are_fired=True)`
to your function to validate that all requests were executed in the wrapped function. See #183