Update appveyor.yml

fiddeling with yml

Author: stesee

appveyor.yml

@@ -1,12 +1,15 @@
 version: 1.0.{build}
-skip_tags: true
 image: Visual Studio 2019
+skip_tags: true
+branches:
+  only:
+  - master
 configuration: Release
 before_build:
 - ps: >-
     nuget restore
-    . "C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\x64\sn.exe" -k ./PostScriptValidator/PostScriptValidator.snk
 
+    . "C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\x64\sn.exe" -k ./PostScriptValidator/PostScriptValidator.snk
 build:
   project: PostScriptValidator.sln
   verbosity: minimal