Update dependencies from https://github.com/dotnet/winforms build 20200728.1

Microsoft.Private.Winforms
 From Version 5.0.0-rc.1.20370.3 -> To Version 5.0.0-rc.1.20378.1

Dependency coherency updates

Microsoft.Win32.Registry,System.CodeDom,System.Configuration.ConfigurationManager,System.Diagnostics.EventLog,System.DirectoryServices,System.Drawing.Common,System.Reflection.MetadataLoadContext,System.Security.AccessControl,System.Security.Cryptography.Xml,System.Security.Permissions,System.Security.Principal.Windows,System.Windows.Extensions,Microsoft.NETCore.Platforms,System.IO.Packaging,Microsoft.NETCore.ILDAsm,Microsoft.NETCore.ILAsm,System.Resources.Extensions,Microsoft.NETCore.App.Internal
 From Version 5.0.0-preview.8.20363.2 -> To Version 5.0.0-rc.1.20371.13 (parent: Microsoft.Private.Winforms

eng/Version.Details.xml

 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Private.Winforms" Version="5.0.0-rc.1.20377.6">
+    <Dependency Name="Microsoft.Private.Winforms" Version="5.0.0-rc.1.20378.1">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>47856f874bc3fdea94987dd3f66856ebea864154</Sha>
+      <Sha>a26100251fc55f1a535b78b75da678ee68bffb9f</Sha>
     </Dependency>
     <Dependency Name="Microsoft.Win32.Registry" Version="5.0.0-rc.1.20371.13" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>

eng/Versions.props

@@ -9,7 +9,7 @@
   </PropertyGroup>
   <!-- NuGet Package Versions -->
   <PropertyGroup>
-    <MicrosoftPrivateWinformsVersion>5.0.0-rc.1.20377.6</MicrosoftPrivateWinformsVersion>
+    <MicrosoftPrivateWinformsVersion>5.0.0-rc.1.20378.1</MicrosoftPrivateWinformsVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/coreclr -->
   <PropertyGroup>