Bump flask-caching from 1.8.0 to 1.9.0

Bumps [flask-caching](https://github.com/sh4nks/flask-caching) from 1.8.0 to 1.9.0.
- [Release notes](https://github.com/sh4nks/flask-caching/releases)
- [Changelog](https://github.com/sh4nks/flask-caching/blob/master/CHANGES)
- [Commits](https://github.com/sh4nks/flask-caching/compare/v1.8.0...v1.9.0)

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

setup.py

@@ -37,7 +37,7 @@ setup(
         'Flask-Migrate==2.5.3',
         'Flask-Bootstrap==3.3.7.1',
         'Flask-WTF==0.14.3',
-        'Flask-Caching==1.8.0',
+        'Flask-Caching==1.9.0',
         'geopy==1.22.0',
         'celery==4.4.3',
         'redis==3.5.3',