Remove VC-2013 support. (dmlc#4701)

trivialfis · web-flow · commit 59bc1ef330eb · 2019-07-25T01:28:51.000-04:00
* Removing it as it is not fully c++11 compliance.
diff --git a/appveyor.yml b/appveyor.yml
@@ -2,10 +2,6 @@ environment:
     R_ARCH: x64
     USE_RTOOLS: true
     matrix:
-        - target: msvc
-          ver: 2013
-          generator: "Visual Studio 12 2013 Win64"
-          configuration: Release
         - target: msvc
           ver: 2015
           generator: "Visual Studio 14 2015 Win64"
