Bump AppVeyor to use Visual Studio 2015

This is a work around for sass/libsass#1719 which removed a header that broke compilation on VS 2013.
xzyfer · Nov 11, 2015 · d56794b · d56794b
1 parent 4960fdb
commit d56794b
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/appveyor.yml b/appveyor.yml
@@ -1,3 +1,5 @@
+os: Visual Studio 2015
+
 -
   branches:
     only: