Bump cornice from 3.6.1 to 4.0.1

Bumps [cornice](https://github.com/mozilla-services/cornice) from 3.6.1 to 4.0.1.
- [Release notes](https://github.com/mozilla-services/cornice/releases)
- [Changelog](https://github.com/Cornices/cornice/blob/master/CHANGES.txt)
- [Commits](Cornices/cornice@3.6.1...4.0.1)

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

requirements.txt

@@ -4,7 +4,7 @@ cffi==1.13.2
 chardet==3.0.4
 colander==1.7.0
 colorama==0.4.1
-cornice==3.6.1
+cornice==4.0.1
 cornice-swagger==0.7.0
 dockerflow==2019.10.0
 hupper==1.9.1