Change to build packages only from master

Temp change for 2.0 release to stop dev packages being released.

Author: merbla

appveyor.yml

@@ -19,11 +19,11 @@ deploy:
     secure: nvZ/z+pMS91b3kG4DgfES5AcmwwGoBYQxr9kp4XiJHj25SAlgdIxFx++1N0lFH2x
   skip_symbols: true
   on:
-    branch: /^(dev|master)$/
+    branch: master
 - provider: GitHub
   auth_token:
     secure: ggZTqqV1z0xecDoQbeoy3A7xikShCt9FWZIGp95dG9Fo0p5RAT9oGU0ZekHfUIwk
   artifact: /Serilog.*\.nupkg/
   tag: v$(appveyor_build_version)
   on:
-    branch: master
+    branch: master