tox: Remove 'release' target

Travis does this for us now.

Signed-off-by: Stephen Finucane <stephen@that.guru>

Author: stephenfin

tox.ini

@@ -33,14 +33,6 @@ deps =
 commands =
     python setup.py --command-packages=click_man.commands man_pages
 
-[testenv:release]
-deps =
-    -r{toxinidir}/requirements.txt
-    twine
-commands =
-    python setup.py -q bdist_wheel sdist
-    twine upload --skip-existing {toxinidir}/dist/*
-
 [flake8]
 show-source = True