Wheel not wheels

jsmnbom · jsmnbom · commit 4b16d0937b9d · 2017-06-22T16:28:13.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -20,7 +20,7 @@ before_cache:
 
 install:
   - pip install coveralls
-  - pip install -U wheels
+  - pip install -U wheel
   - pip install -r requirements.txt
   - pip install -r requirements-dev.txt
   - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then pip install ujson; fi
