👷 Travis: Try to use trusty for Python 2.6

.travis.yml

@@ -1,13 +1,13 @@
 language: python
 matrix:
   include:
+    - python: 2.6
+      dist: trusty
     - python: 2.7
     - python: 3.4
     - python: 3.5
     - python: 3.6
     - python: 3.7
-      dist: xenial
-      sudo: true
 
 
 # command to run tests