fix: Resolve 'CryptographyDeprecationWarning' (#341)
fix: Resolve 'CryptographyDeprecationWarning' (#341)

The 'paramiko' python module depends on the 'cryptography' module. There
is a known 'CryptographyDeprecationWarning' problem (see
https://github.com/paramiko/paramiko/issues/1369) that can be resolved
by installing 'cryptography==2.4.2'.
open-power-ref-design-toolkit/cluster-genesis,open-power-ref-design-toolkit/cluster-genesis