Bump flask from 0.12.2 to 1.0

Bumps [flask](https://github.com/pallets/flask) from 0.12.2 to 1.0.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/master/CHANGES.rst)
- [Commits](pallets/flask@0.12.2...1.0)

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

requirements.txt

@@ -11,7 +11,7 @@ Sphinx==1.7 # Updated from 1.6.3
 sphinxcontrib-napoleon==0.6.1
 betamax==0.8.0
 betamax-serializers==0.2.0
-Flask==0.12.2
+Flask==1.0
 flask-restplus==0.10.1
 Flask-OAuthlib==0.9.4
 flask-basicauth==0.2.0