Bump flask-cors from 3.0.4 to 3.0.9

Bumps [flask-cors](https://github.com/corydolphin/flask-cors) from 3.0.4 to 3.0.9.
- [Release notes](https://github.com/corydolphin/flask-cors/releases)
- [Changelog](https://github.com/corydolphin/flask-cors/blob/master/CHANGELOG.md)
- [Commits](corydolphin/flask-cors@3.0.4...3.0.9)

---
updated-dependencies:
- dependency-name: flask-cors
  dependency-type: direct:production
...

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

requirements.txt

@@ -1,5 +1,5 @@
 Flask_Limiter==1.0.1
 Flask==1.0
-Flask_Cors==3.0.4
+Flask_Cors==3.0.9
 docker==3.3.0
 docker-pycreds==0.2.3