Remove some requirements only needed on python 3.6
Remove some requirements only needed on python 3.6

crawln45/Flexget,ianstalk/Flexget,Flexget/Flexget,malkavi/Flexget,crawln45/Flexget,malkavi/Flexget,Flexget/Flexget,Flexget/Flexget,ianstalk/Flexget,ianstalk/Flexget,Flexget/Flexget,crawln45/Flexget,malkavi/Flexget,crawln45/Flexget,malkavi/Flexget