Upgrade gensim

I can't get the fast C binding stuff working on Amazon Linux, so the
features involving processing uploaded text fail (they rely on a code
path that only exists with the fast C backing). I'd still like to get
it working for the sake of speed, but in the meantime, I'd like the
feature to work at all.

I tried the next minor version of gensim (3.3.0) but it failed due to
the bug fixed in this PR, which was incorporated into 3.5.0:
piskvorky/gensim#1974

So I'm using the lowest gensim version which passes the tests. It's way
out of date now but I don't want to open up the upgrade can of worms.

Pipfile

@@ -12,7 +12,6 @@ django = {version = "~=2.2.0"}
 gunicorn = "*"
 gevent = "*"
 coverage = "*"
-gensim = {version = "~=3.2.0"}
 nltk = "*"
 tika = "*"
 whitenoise = "*"
@@ -28,7 +27,8 @@ chardet = "*"
 django-health-check = "*"
 raven = "*"
 boto = "==2.48.0"
-psycopg2 = "==2.8.6"
+psycopg2 = "*"
+gensim = "~=3.5.0"
 
 [requires]
 python_version = "3.8"