Remove unused appveyor.yml

appveyor.yml

@@ -1,35 +0,0 @@
-version: 1.0.{build}
-branches:
-  only:
-    - dev
-
-skip_tags: true
-
-skip_commits:
-  files:
-    - '.github/**'
-    - '**.md'
-    - 'scripts/*'
-
-image: Visual Studio 2019
-
-install:
-  - git submodule update --init --depth 1
-
-platform: x64
-
-configuration: ReleaseLTCG
-
-build:
-  parallel: true
-  project: duckstation.sln
-
-after_build:
-  - |-
-      7z a  duckstation-windows-x64-release.zip .\bin\x64\* -r "-xr!*.pdb" "-xr!common-tests*"
-      7z rn duckstation-windows-x64-release.zip updater-x64-ReleaseLTCG.exe updater.exe
-
-test: off
-
-artifacts:
-  - path: duckstation-windows-x64-release.zip