Update dependencies from https://github.com/dotnet/winforms build 20200218.2 (#2610)

- Microsoft.Private.Winforms - 5.0.0-preview.2.20118.2

eng/Version.Details.xml

 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Private.Winforms" Version="5.0.0-preview.1.20118.1">
+    <Dependency Name="Microsoft.Private.Winforms" Version="5.0.0-preview.2.20118.2">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>d542887a907b98757a359078c3b4c25bf01b6837</Sha>
+      <Sha>ca28124687f80028e3f8e38671de0f9918970351</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>

eng/Versions.props

@@ -9,7 +9,7 @@
   </PropertyGroup>
   <!-- NuGet Package Versions -->
   <PropertyGroup>
-    <MicrosoftPrivateWinformsVersion>5.0.0-preview.1.20118.1</MicrosoftPrivateWinformsVersion>
+    <MicrosoftPrivateWinformsVersion>5.0.0-preview.2.20118.2</MicrosoftPrivateWinformsVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/coreclr -->
   <PropertyGroup>