Bump cryptography from 3.3.1 to 3.4.1

Bumps [cryptography](https://github.com/pyca/cryptography) from 3.3.1 to 3.4.1.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/master/CHANGELOG.rst)
- [Commits](pyca/cryptography@3.3.1...3.4.1)

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

requirements.txt

@@ -7,7 +7,7 @@ colander==1.8.3
 colorama==0.4.4
 cornice==5.0.3
 cornice-swagger==1.0.0
-cryptography==3.3.1
+cryptography==3.4.1
 dockerflow==2020.10.0
 hupper==1.10.2
 idna==3.1