build(deps): bump cryptography from 2.6.1 to 3.2

Bumps [cryptography](https://github.com/pyca/cryptography) from 2.6.1 to 3.2.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/master/CHANGELOG.rst)
- [Commits](pyca/cryptography@2.6.1...3.2)

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

requirements.txt

@@ -59,7 +59,7 @@ configparser==3.7.4
 contextlib2==0.5.5
 cookiecutter==1.6.0
 counter-robots==2018.6
-cryptography==2.6.1
+cryptography==3.2
 datacite==1.0.1
 dcxml==0.1.1
 decorator==4.4.0