CVE-2020-1967 - upgrade cryptography library 2.8 to 2.9.1

[jamiemccrindle]

Version 2.8 of the cryptography library contains CVE-2020-1967 could you upgrade to 2.9.1?

https://nvd.nist.gov/vuln/detail/CVE-2020-1967

[yonzhan]

Jiashuo Li (@jiasli) for awareness.

[jiasli]

Will be addressed in #15687.

[fengzhou-msft]

cryptography is upgraded to 3.3.2. A new version of azure-cli with this change will be released on 3/2.