Merge branch 'remove-olefile' into 'master'

Remove olefile dependency

Closes #476

See merge request !1002

requirements.txt

@@ -18,7 +18,6 @@ elasticsearch-dsl>=6.0.0,<7.0.0
 gitpython==3.0.8
 idna==2.10
 jdcal==1.3
-olefile==0.44
 python-gitlab==1.7.0
 python-memcached==1.59
 pytz>=2018.7