Re-added os image specifier

Simon Hofmann · Simon Hofmann · commit 4f8491614c13 · 2019-09-24T16:34:08.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -7,14 +7,17 @@ matrix:
     - os: linux
       node_js: "10"
     - os: osx
+      osx_image: xcode11
       node_js: "10"
     - os: linux
       node_js: "11"
     - os: osx
+      osx_image: xcode11
       node_js: "11"
     - os: linux
       node_js: "12"
     - os: osx
+      osx_image: xcode11
       node_js: "12"
 
 addons:
