attempt to fix ci issue

tox.ini

 [tox]
-envlist = py37, py37-ci, style, docs, benchmarks
+envlist = py37, style, docs
 
 [testenv]
 commands=
     pip install -r requirements_dev.txt
-    pip install --extra-index-url http://pypi-sissource.ethz.ch/simple/ --trusted-host pypi-sissource.ethz.ch -e .
+    pip install --extra-index-url http://pypi-sissource.ethz.ch/simple/ --trusted-host pypi-sissource.ethz.ch .
     pytest --cov emzed/ext/mzmine2 --cov-report term --cov-report html tests