version requirements for cryptography should be consistent

[suliuzh]

Hi
It seems that version requirements for cryptography in setup.py and requirements.txt are not consistent
In setup.py, it is cryptography>=1.3.4
In requirements.txt, it is cryptography==3.2
Note that in pypi, the version of cryptography is always updating( now 3.4.6). Inconsistent version requirements will result in installing different version for cryptography if I use different ways of installation.