Fix Travis

jeroen · jeroen · commit 46c2ef637f7d · 2020-01-22T01:38:26.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -9,6 +9,8 @@ matrix:
     - r: 3.3
       addons:
         apt:
+          sources:
+            - sourceline: 'ppa:cran/travis'
           packages: libnode-dev
     - r: release
     - r: release
