Bump gensim from 3.3.0 to 3.7.1 (#229)

Bumps [gensim](https://github.com/RaRe-Technologies/gensim) from 3.3.0 to 3.7.1.
- [Release notes](https://github.com/RaRe-Technologies/gensim/releases)
- [Changelog](https://github.com/RaRe-Technologies/gensim/blob/develop/CHANGELOG.md)
- [Commits](piskvorky/gensim@3.3.0...3.7.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

requirements.txt

@@ -9,7 +9,7 @@ psycopg2==2.7.3.2
 SQLAlchemy==1.2.17
 Flask==0.12.4
 Flask-Cors==3.0.3
-gensim==3.3.0
+gensim==3.7.1
 lxml==4.3.0
 pyLDAvis==2.1.2
 ratelimit==1.4.1