- Correct Tox release environment.

tox.ini

@@ -37,6 +37,6 @@ deps =
     twine
     wheel
 commands =
-    sh -c 'git tag "$(cat VERSION)" && git push --tags'
+    sh -c 'git tag "v$(cat VERSION)" && git push --tags'
     python setup.py bdist_wheel
     twine upload --skip-existing dist/*.whl