add ruby 2.5 to appveyor

Colby Swandale · Colby Swandale · commit f5321b33d693 · 2018-11-06T18:35:28.000+11:00
diff --git a/appveyor.yml b/appveyor.yml
@@ -29,4 +29,6 @@ environment:
     - ruby_version: 23-x64
     - ruby_version: 24
     - ruby_version: 24-x64
+    - ruby_version: 25
+    - ruby_version: 25-x64
     - ruby_version: _trunk
