set osx_image in .travis.yml to test on OSX Catalina

dgpv · dgpv · commit 47384c0a8f18 · 2020-07-13T09:23:01.000+05:00
diff --git a/.travis.yml b/.travis.yml
@@ -12,6 +12,8 @@ os:
   - linux
   - osx
 
+osx_image: xcode12
+
 branches:
   only:
   - gh-pages
