fix: Upgrade tox

Author: untitaker

scripts/runtox.sh

@@ -10,4 +10,4 @@ else
     searchstring="$1"
 fi
 
-exec tox -e $(tox -l | grep $searchstring | tr '\n' ',') -- "${@:2}"
+exec tox -p auto -e $(tox -l | grep $searchstring | tr '\n' ',') -- "${@:2}"

test-requirements.txt

@@ -1,7 +1,7 @@
 hypothesis==3.69.9
 pytest==3.7.3
 pytest-xdist==1.23.0
-tox==3.2.1
+tox==3.7.0
 Werkzeug==0.14.1
 pytest-localserver==0.4.1
 pytest-cov==2.6.0