Bump future from 0.18.2 to 0.18.3 in /requirements

Bumps [future](https://github.com/PythonCharmers/python-future) from 0.18.2 to 0.18.3.
- [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...v0.18.3)

---
updated-dependencies:
- dependency-name: future
  dependency-type: direct:production
...

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

requirements/requirements.txt

@@ -31,7 +31,7 @@ Flask-Migrate==2.5.3
 Flask-SQLAlchemy==2.4.4
 Flask-Limiter==1.4
 limits==1.5.1
-future==0.18.2
+future==0.18.3
 graphviz==0.14.1
 gunicorn==20.1.0
 idna==2.10