Remove tox from dev-requirements (urllib3#1666)

pquentin · sethmlarson · commit 17e5fbd4ad28 · 2019-08-28T19:03:57.000-05:00
diff --git a/dev-requirements.txt b/dev-requirements.txt
@@ -1,6 +1,5 @@
 mock==2.0.0
 coverage~=4.5
-tox==2.9.1
 wheel==0.30.0
 tornado==5.1.1
 PySocks==1.6.8
