.travis.yml in fluent-plugin-out-http-1.3.2 vs .travis.yml in fluent-plugin-out-http-1.3.3

@@ -1,15 +1,14 @@
 rvm:
-  - 2.2
-  - 2.3
-  - 2.4.5
-  - 2.5.3
-  - 2.6.0
+  - 2.4.6
+  - 2.5.6
+  - 2.6.4
   - ruby-head
 
 os:
   - linux
   - osx
+osx_image: xcode11.2
 
 dist: trusty
 
 gemfile:
   - Gemfile