Remove dev and master from v1.x build branches (#6363)

Author: gzuber

appveyor.yml

@@ -10,8 +10,6 @@ pull_requests:
   do_not_increment_build_number: true
 branches:
   only:
-  - dev
-  - master
   - v1.x
 max_jobs: 1
 image: Visual Studio 2017
@@ -38,4 +36,4 @@ artifacts:
     name: NuGet
 hosts:
   api.nuget.org: 93.184.221.200
-  dist.nuget.org: 93.184.221.200
+  dist.nuget.org: 93.184.221.200