Bump cryptography from 2.3 to 3.2 (#28)

Bumps [cryptography](https://github.com/pyca/cryptography) from 2.3 to 3.2.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/master/CHANGELOG.rst)
- [Commits](pyca/cryptography@2.3...3.2)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -16,7 +16,7 @@ cffi==1.13.2
 cfgv==1.0.0
 chardet==3.0.4
 click==7.1.2
-cryptography==2.3
+cryptography==3.2
 csh-ldap==2.2.0
 dataclasses==0.7
 defusedxml==0.6.0