Remove mock from install_requires
Remove mock from install_requires

`mock` is not used anywhere currently. Furthermore, pinning to an exact version of mock forces all users of this library to have `mock==1.0.1` installed which is rediculous.
not-napoleon/schematics,openprocurement/schematics,kaiix/schematics,eatfirst/schematics,mlyundin/schematics,NerdWallet/schematics,not-napoleon/schematics