Bump flask from 0.12.3 to 1.0

Bumps [flask](https://github.com/pallets/flask) from 0.12.3 to 1.0.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/master/CHANGES.rst)
- [Commits](pallets/flask@0.12.3...1.0)

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

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 appdirs==1.4.0
 pyee==5.0.0
-flask==0.12.3
+flask==1.0
 packaging==16.8
 pyparsing==2.1.10
 six==1.10.0