Bump future from 0.18.2 to 1.0.0 in /src/Backend

Bumps [future](https://github.com/PythonCharmers/python-future) from 0.18.2 to 1.0.0.
- [Release notes](https://github.com/PythonCharmers/python-future/releases)
- [Changelog](https://github.com/PythonCharmers/python-future/blob/master/docs/changelog.rst)
- [Commits](PythonCharmers/python-future@v0.18.2...v1.0.0)

---
updated-dependencies:
- dependency-name: future
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>