Bug fixes and enhancements:
- bump cryptography from 3.2 to 3.3.2 (#21)
- bump pyyaml from 5.2 to 5.4 (#23)
- bump rsa from 3.4.2 to 4.7 (#24)
- bump urllib3 from 1.25.7 to 1.25.8 (#25)
- hotfix CircleCI failures (#26)
- require mock
- add moto to requirements
- bump version
