Update appveyor.yml

appveyor/ci#1986 (comment)

Author: Ilya Finkelshteyn

appveyor.yml

@@ -1,10 +1,6 @@
 version: '{build}'
 pull_requests:
   do_not_increment_build_number: true
-branches:
-  only:
-  - master
-  - develop
 environment:
   NugetAPIKey:
     secure: zvkaZiaBXVko+3ZzuSb7W6DTUJmHX98XgEhKs28SnGD+4TM3gzhPxVnNWSmBhXEx
@@ -37,4 +33,7 @@ for:
     - master
   build_script:
   - ps: .\build.ps1 -Revision "$env:APPVEYOR_BUILD_NUMBER"
-
+-
+  branches:
+    only:
+    - develop