Bump cornice from 5.0.1 to 5.0.3

Bumps [cornice](https://github.com/mozilla-services/cornice) from 5.0.1 to 5.0.3.
- [Release notes](https://github.com/mozilla-services/cornice/releases)
- [Changelog](https://github.com/Cornices/cornice/blob/master/CHANGES.txt)
- [Commits](Cornices/cornice@5.0.1...5.0.3)

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

requirements.txt

@@ -4,7 +4,7 @@ cffi==1.14.1
 chardet==3.0.4
 colander==1.8.2
 colorama==0.4.3
-cornice==5.0.1
+cornice==5.0.3
 cornice-swagger==1.0.0
 dockerflow==2020.6.0
 hupper==1.10.2