Remove branch condition for AppVeyor deploy

Apparently:

"However, please note that in case of annotated tag, branch and
APPVEYOR_REPO_TAG are mutually exclusive. This is because, for webhook
created as a result of annotated tag, there is no practical reliable
way to recognize what branch the tag was created from."

appveyor.yml

@@ -60,7 +60,6 @@ deploy:
   artifact: /dstep.+\.7z/
   draft: true
   on:
-    branch: master
     appveyor_repo_tag: true
     configuration: LLVM 8.0.0
     d: ldc