Bump flask-cors from 3.0.3 to 3.0.7

Bumps [flask-cors](https://github.com/corydolphin/flask-cors) from 3.0.3 to 3.0.7.
- [Release notes](https://github.com/corydolphin/flask-cors/releases)
- [Changelog](https://github.com/corydolphin/flask-cors/blob/master/CHANGELOG.md)
- [Commits](corydolphin/flask-cors@3.0.3...3.0.7)

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

requirements.txt

@@ -8,7 +8,7 @@ boto3==1.9.86
 psycopg2==2.7.3.2
 SQLAlchemy==1.2.17
 Flask==1.0.2
-Flask-Cors==3.0.3
+Flask-Cors==3.0.7
 gensim==3.7.1
 lxml==4.3.0
 pyLDAvis==2.1.2