use APPVEYOR_BUILD_WORKER_IMAGE

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65021 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2018-10-12 00:45:07 +00:00 · 2018-10-12 00:45:07 +00:00 · 9d1aab4301
--- a/appveyor.yml
+++ b/appveyor.yml
@ -9,12 +9,12 @@ environment:
  matrix:
    - build: vs
      vs: 120
-      image: Visual Studio 2013
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
    - build: vs
      vs: 140
-      image: Visual Studio 2015
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
    - build: msys2
-      image: Visual Studio 2015
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
 matrix:
  fast_finish: true
 notifications: