Bump cryptography from 2.8 to 3.2 (#138)

Bumps [cryptography](https://github.com/pyca/cryptography) from 2.8 to 3.2.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/pyca/cryptography/compare/2.8...3.2)

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

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

requirements.txt

@@ -2,7 +2,7 @@ beautifulsoup4==4.8.2
 bs4==0.0.1
 cffi==1.13.2
 Click==7.0
-cryptography==2.8
+cryptography==3.2
 Flask==1.1.1
 Flask-Session==0.3.2
 itsdangerous==1.1.0