Tox: fix after removal of Poetry

sybrenstuvel · sybrenstuvel · commit fb8772a34b90 · 2020-06-11T20:22:30.000+02:00
diff --git a/tox.ini b/tox.ini
@@ -1,7 +1,6 @@
 [tox]
 # Environment changes have to be manually synced with '.travis.yml'.
 envlist = py35,py36,p37,p38
-isolated_build = true
 
 [pytest]
 addopts = -v --cov rsa --cov-report term-missing
