Update responses requirement in /server

Updates the requirements on [responses](https://github.com/getsentry/responses) to permit the latest version.
- [Release notes](https://github.com/getsentry/responses/releases)
- [Changelog](https://github.com/getsentry/responses/blob/master/CHANGES)
- [Commits](getsentry/responses@0.10.6...0.25.0)

---
updated-dependencies:
- dependency-name: responses
  dependency-type: direct:development
...

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

server/dev-requirements.txt

@@ -6,7 +6,7 @@ sphinx-autobuild
 pytest==3.10.0
 pytest-cov==2.6.1
 pytest-mock==1.10.1
-responses>=0.10.6,<0.11
+responses>=0.10.6,<0.26
 httmock
 wooper
 mypy