build(deps-dev): bump responses from 0.10.15 to 0.11.0 in /backend (#589)

Bumps [responses](https://github.com/getsentry/responses) from 0.10.15 to 0.11.0.
- [Release notes](https://github.com/getsentry/responses/releases)
- [Changelog](https://github.com/getsentry/responses/blob/master/CHANGES)
- [Commits](getsentry/responses@0.10.15...0.11.0)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/requirements-dev.txt

@@ -2,4 +2,4 @@ fakeredis==1.4.1
 pre-commit==2.6.0
 pytest==6.0.1
 pytest-responses==0.4.0
-responses==0.10.15
+responses==0.11.0