Update .travis.yml

.travis.yml

@@ -1,6 +1,5 @@
-language: python
-python:
-- '3.6'
+language: generic
+
 addons:
   apt:
     packages:
@@ -21,7 +20,8 @@ addons:
     
 cache:
   - pip
-
+  directories:
+    - $HOME/.cache/pip
 sudo: required
 
 dist: trusty
@@ -43,16 +43,19 @@ matrix:
 install:
 - |
   if [ $TRAVIS_OS_NAME = "linux" ]; then
+    curl -L https://github.com/pyenv/pyenv-installer/raw/master/bin/pyenv-installer | bash
+    pyenv install 3.6.7
+    export PATH="/home/travis/.pyenv/shims:${PATH}"
     export DISPLAY=:99.0
     /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX +render -noreset
     sleep 3
   elif [ $TRAVIS_OS_NAME = "osx" ]; then
     CFLAGS="-I$(xcrun --show-sdk-path)/usr/include" pyenv install 3.6.7
-    export PYENV_VERSION=3.6.7
     export PATH="/Users/travis/.pyenv/shims:${PATH}"
-    pyenv-virtualenv venv
-    source venv/bin/activate
   fi
+  export PYENV_VERSION=3.6.7
+  pyenv-virtualenv venv 3.6.7
+  source venv/bin/activate
 
 - pip install .
 - pip install borgbackup