Is your feature request related to a problem? Please describe.

Currently Azure CLI can't be installed on Python 3.9, causing different errors on different platforms.

For example, on Windows

Building wheels for collected packages: bcrypt, cryptography, PyNaCl
...
  Building wheel for cryptography (PEP 517) ... error
  building '_openssl' extension
  error: Microsoft Visual C++ 14.0 or greater is required. Get it with "Microsoft C++ Build Tools": https://visualstudio.microsoft.com/visual-cpp-build-tools/
  ----------------------------------------
  ERROR: Failed building wheel for cryptography

This is because older versions of bcrypt, cryptography, PyNaCl don't distribute wheels for Python 3.9. For example, cryptography 2.9.2 only distributes cryptography-2.9.2-cp38-cp38-win_amd64.whl.

Users will have to either

• install gcc or Microsoft Visual C++ to build these dependencies from source, or
• use an older version of Python (Note whether azure-cli really needs an old version of Python MicrosoftDocs/azure-docs-cli#2407).

Describe the solution you'd like

The latest versions of bcrypt, cryptography, PyNaCl all use Stable Application Binary Interface (*-cp36-abi3-win_amd64.whl) to build wheels so that they can be installed on Python 3.9 without building source code.

Azure CLI should support Python 3.9 by bumping these dependencies:

• bcrypt 3.2: {Packaging} Bump bcrypt and PyNaCl #17369
• cryptography 3.3.1: {Packaging} Bump cryptography from 2.8 to 3.3.2 #15687
• PyNaCl 1.4: {Packaging} Bump bcrypt and PyNaCl #17369