Update files copied from dotnet/arcade

Directory.Build.props

@@ -11,17 +11,6 @@
     <DebugType>embedded</DebugType>
     <DebugSymbols>true</DebugSymbols>
 
-    <!--
-      Tools and packages produced by this repository support infrastructure and are not shipping on NuGet or via any other official channel.
-    -->
-    <IsShipping>false</IsShipping>
-  </PropertyGroup>
-
-  <PropertyGroup>
-    <!-- 
-      'NetFxTfm' is the standard desktop Target Framework Moniker which this repo's packages are targeting
-      ie.  Place 'NetFxTfm' in the 'TargetFramework' property of a csproj like <TargetFrameworks>$(NetFxTfm);netcoreapp2.0</TargetFrameworks> 
-    -->
-    <NetFxTfm>net461</NetFxTfm>
+    <IsShipping>true</IsShipping>
   </PropertyGroup>
 </Project>

global.json

@@ -1,6 +1,6 @@
 {
   "tools": {
-    "dotnet": "2.1.400-preview-009088"
+    "dotnet": "3.0.100-preview1-009020"
   },
   "msbuild-sdks": {
     "Microsoft.DotNet.Arcade.Sdk": "1.0.0-beta.18520.3"