Loosen package requirements incl cryptography

[ciarancourtney]

Hi,

Could you consider loosening your dependancies unless there are technical reasons to do so? For example right now cryptography v42 cannot be installed alongside frontegg v3.0.0. Instead of specifying^41.0 could you set a minimum version or just * if that works?

[hxyannay]

Hey, did this specifically for cryptography in #124
Would be good if anyone from the team can look at it and merge & release a new version.