Added appveyor build script

[release]

Author: madskristensen

README.md

@@ -2,6 +2,8 @@
 
 Part of the [VSIX Community](https://github.com/VsixCommunity)
 
+[![Build status](https://ci.appveyor.com/api/projects/status/6y2vim0h3c9nvlxk?svg=true)](https://ci.appveyor.com/project/madskristensen/community-visualstudio-sourcegenerators)
+
 ## Summary
 
 This package contains [C# source generators](https://docs.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/source-generators-overview) that generate code from `.vsixmanfiest` files and `.vsct` files.

appveyor.yml

@@ -0,0 +1,28 @@
+image: Visual Studio 2022
+
+install:
+   # .NET Core SDK binaries
+  - ps: $urlCurrent = "https://download.visualstudio.microsoft.com/download/pr/8e55ce37-9740-41b7-a758-f731043060da/4b8bfd4aad9d322bf501ca9e473e35c5/dotnet-sdk-6.0.101-win-x64.zip"
+  - ps: $env:DOTNET_INSTALL_DIR = "$pwd\.dotnetsdk"
+  - ps: mkdir $env:DOTNET_INSTALL_DIR -Force | Out-Null
+  - ps: $tempFileCurrent = [System.IO.Path]::GetTempFileName()
+  - ps: (New-Object System.Net.WebClient).DownloadFile($urlCurrent, $tempFileCurrent)
+  - ps: Add-Type -AssemblyName System.IO.Compression.FileSystem; [System.IO.Compression.ZipFile]::ExtractToDirectory($tempFileCurrent, $env:DOTNET_INSTALL_DIR)
+  - ps: $env:Path = "$env:DOTNET_INSTALL_DIR;$env:Path"
+
+build_script:
+  - ps: $env:MinorVersion = "0.$($env:appveyor_build_number)"
+  - ps: MSBuild -restore /p:configuration=Release /p:ContinuousIntegrationBuild=true
+ 
+artifacts:
+  - path: _Packages\*.nupkg
+    name: NuGet package
+
+deploy:
+  - provider: NuGet
+    artifact: /NuGet/
+    api_key:
+      secure: ykKSUjAVYCP1SdG2u5b7S7jiRhFrTBbnwdvwLYmY6T6sivZk33zHuPEQGQz6gp7X
+    on:
+      branch: main
+      appveyor_repo_commit_message_extended: /\[release\]/