Update dependencies from https://github.com/dotnet/winforms build 20190815.7 (#1643)

- Microsoft.Private.Winforms - 4.8.0-preview9.19415.7

Dependency coherency updates

- Microsoft.NETCore.App - 3.0.0-preview9-19415-06 (parent: Microsoft.Private.Winforms)

eng/Version.Details.xml

 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Private.Winforms" Version="4.8.0-preview9.19415.2">
+    <Dependency Name="Microsoft.Private.Winforms" Version="4.8.0-preview9.19415.7">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>580f3a9409cffc3d6f1a2cc01135dc984d5ab890</Sha>
+      <Sha>1d3d1ea7a7a5643ef473f92eb727591512fbda8f</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
@@ -59,9 +59,9 @@
       <Uri>https://github.com/dotnet/corefx</Uri>
       <Sha>b82d2bc44424c8a99a1f0fc13202bdfd43e6f9f5</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App" Version="3.0.0-preview9-19415-04" CoherentParentDependency="Microsoft.Private.Winforms">
+    <Dependency Name="Microsoft.NETCore.App" Version="3.0.0-preview9-19415-06" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/core-setup</Uri>
-      <Sha>42b6555ce2c1094e92bdb19b5a279f854c2bf60c</Sha>
+      <Sha>4596024c95731f298a42d8bd050a2951aed4e91b</Sha>
     </Dependency>
     <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="1.0.0-beta.19411.1">
       <Uri>https://github.com/dotnet/arcade</Uri>

eng/Versions.props

@@ -8,7 +8,7 @@
   </PropertyGroup>
   <!-- NuGet Package Versions -->
   <PropertyGroup>
-    <MicrosoftPrivateWinformsVersion>4.8.0-preview9.19415.2</MicrosoftPrivateWinformsVersion>
+    <MicrosoftPrivateWinformsVersion>4.8.0-preview9.19415.7</MicrosoftPrivateWinformsVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/coreclr -->
   <PropertyGroup>
@@ -18,7 +18,7 @@
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/core-setup -->
   <PropertyGroup>
-    <MicrosoftNETCoreAppVersion>3.0.0-preview9-19415-04</MicrosoftNETCoreAppVersion>
+    <MicrosoftNETCoreAppVersion>3.0.0-preview9-19415-06</MicrosoftNETCoreAppVersion>
     <MicrosoftNETCorePlatformsVersion>3.0.0-preview9.19409.17</MicrosoftNETCorePlatformsVersion>
     <SystemDrawingCommonVersion>4.6.0-preview9.19409.17</SystemDrawingCommonVersion>
     <SystemDirectoryServicesVersion>4.6.0-preview9.19409.17</SystemDirectoryServicesVersion>