Enable automatic updates to Eng/Common through Microsoft.WinAppSDK.EngCommon toolset dependency (#1888)

NuGet.config

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <packageSources>
     <clear />

eng/Version.Details.xml

@@ -3,5 +3,9 @@
   <ProductDependencies>
   </ProductDependencies>
   <ToolsetDependencies>
+    <Dependency Name="Microsoft.WinAppSDK.EngCommon" Version="1.0.0-20211207.1-CI">
+      <Uri>https://dev.azure.com/microsoft/ProjectReunion/_git/ProjectReunionInternal</Uri>
+      <Sha>4aca9667c547d389569c4f57a997afc6392839d6</Sha>
+    </Dependency>
   </ToolsetDependencies>
 </Dependencies>

global.json

@@ -1,5 +1,8 @@
 {
+  "tools": {
+    "dotnet": "6.0.100"
+  },
   "msbuild-sdks": {
-    "arcade.sdk": "1.1.2"
+    "Microsoft.WinAppSDK.EngCommon": "1.0.0-20211207.1-CI"
   }
 }