fix: pins to a working fork of goslate (dep on django-autotranslate)

[gdixon]

Description

This PR will pin us to a fork of goslate in order to fix our CI build (as well as our local install) following recent changes in setuptools (see here for details: pypa/setuptools#1390)

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I have opened a PR against goslate (zhuoqiang/goslate#2) which will solve this without the need for us to pin anything however it will also require a version bump on django-autotranslate so we should merge this and look to the maintainers of these external libs to roll out a fix.

Refers/Fixes

Failing build on travis (and my local)

Testing

Tested locally

[chibie]

lgtm... your goslate pr has been merged tho 💯

[gdixon]

Closing this out, @zhuoqiang has merged and published my PR - zhuoqiang/goslate#2 (comment) and there are no versions pinned in django_autotranslate (https://github.com/ankitpopli1891/django-autotranslate/blob/master/requirements.txt) so this PR is surplus to requirement 🚀

I think we could also drop django_autotranslate as it doesn't seem to be working - @thelostone-mc - do you know when this was last used?

[thelostone-mc]

This can be retried as it's not been used for a while from what I'm aware