Bump flask from 0.12.2 to 1.0 in /monitor-flask-apps

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] <[email protected]>

Author: dependabot[bot]

monitor-flask-apps/requirements.txt

@@ -1,3 +1,3 @@
 blinker==1.4
-Flask==0.12.2
+Flask==1.0
 rollbar==0.13.12