Travis: use pypy from Xenial, add pypy3

Author: blueyed

.travis.yml

@@ -32,8 +32,10 @@ jobs:
   include:
     # Coverage tracking is slow with pypy, skip it.
     - env: TOXENV=pypy PYTEST_NO_COVERAGE=1
-      python: 'pypy-5.4'
-      dist: trusty
+      python: 'pypy2.7-6.0'
+    - env: TOXENV=pypy3 PYTEST_NO_COVERAGE=1
+      python: 'pypy3.5-6.0'
+
     - env: TOXENV=py34
       python: '3.4'
     - env: TOXENV=py35