Switch Build to use 2.4 with certs files

patched by MSP-Greg <MSP-Greg@users.noreply.github.com>
fix https://github.com/ruby/ruby/pull/1702

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60022 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

appveyor.yml

@@ -3,7 +3,7 @@ shallow_clone: true
 platform:
   - x64
 environment:
-  ruby_version: "23-%Platform%"
+  ruby_version: "24-%Platform%"
   zlib_version: "1.2.11"
   matrix:
     - vs: "120"