Fix docs build on Travis, mk. 2

TheAssassin · TheAssassin · commit d51803ea0b45 · 2019-06-17T14:11:51.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -38,7 +38,8 @@ matrix:
           update: true
           packages:
             - doxygen
-            - python3-pip
+      language: python
+      python: 3.6
       dist: xenial
       script:
         - cd docs && ./make.sh html
