Improve AppVeyor build numbering (#3291)

* Attempts to make the deployed artifact name include the build number.

Author: shadowofsilicon

appveyor.yml

@@ -1,4 +1,4 @@
-version: 2.1.{build}-prerelease
+version: 2.1.0.{build}
 branches:
   only:
   - master
@@ -33,11 +33,11 @@ before_deploy:
 deploy:
 - provider: GitHub
   tag: Rubberduck v$(appveyor_build_version)
-  release: Rubberduck v$(appveyor_build_version)
+  release: Rubberduck v$(appveyor_build_version)-prerelease
   description: AppVeyor build on [next] - https://ci.appveyor.com/project/retailcoder/rubberduck/build/$(appveyor_build_version)
   auth_token:
     secure: oh0SRnZVt0ABeWqFr7ut5TZkxFJjHmS/DZnJnp2HErQTCmX3O8RASJH3ZiYl11gz
-  artifact: Installers\Rubberduck.Setup.exe
+  artifact: Installers\Rubberduck.Setup.$(appveyor_build_version)-prerelease.exe
   draft: false
   prerelease: true
   on: