Use pip 7 caching

.gitlab-ci.yml

@@ -7,7 +7,7 @@ tests:
         - source env/bin/activate
         - curl https://bootstrap.pypa.io/get-pip.py | python
         - cd src
-        - pip3 install -q -r requirements.txt
+        - XDG_CACHE=/cache pip3 install -q -r requirements.txt
         - flake8 --ignore=E123,F403,F401,N802,C901,W503 .
         - isort -c -rc .
         - python3 manage.py check

.travis.yml

@@ -3,6 +3,7 @@ sudo: false
 python:
     - "3.4"
 install:
+    - pip install -U pip wheel
     - pip install -q -r src/requirements.txt
     - npm install -g less@2.5.0
 before_script:
@@ -16,3 +17,4 @@ script:
     - coverage run -m py.test tests
 after_success:
     - coveralls
+cache: pip