Update dependencies from https://github.com/dotnet/winforms build 20200812.5 (#3328)

[release/3.1] Update dependencies from dotnet/winforms
- Updates:
  - Microsoft.Private.Winforms: from 4.8.1-servicing.20411.4 to 4.8.1-servicing.20412.5

Author: dotnet-maestro[bot]

NuGet.config

@@ -15,4 +15,5 @@
     <add key="dotnet-wd" value="https://dotnetfeed.blob.core.windows.net/dotnet-windowsdesktop/index.json" />
     <add key="aspnet-core" value="https://dotnetfeed.blob.core.windows.net/aspnet-aspnetcore/index.json" />
   </packageSources>
+  <disabledPackageSources />
 </configuration>

eng/Version.Details.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.Private.Winforms" Version="4.8.1-servicing.20411.4">
+    <Dependency Name="Microsoft.Private.Winforms" Version="4.8.1-servicing.20412.5">
       <Uri>https://github.com/dotnet/winforms</Uri>
-      <Sha>96f8bef5b7856c14407744fb9fe3fc81d61e8e67</Sha>
+      <Sha>cf28cab9e5142862de29534e688680a239ba781c</Sha>
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>

eng/Versions.props

@@ -18,7 +18,7 @@
   </PropertyGroup>
   <!-- NuGet Package Versions -->
   <PropertyGroup>
-    <MicrosoftPrivateWinformsVersion>4.8.1-servicing.20411.4</MicrosoftPrivateWinformsVersion>
+    <MicrosoftPrivateWinformsVersion>4.8.1-servicing.20412.5</MicrosoftPrivateWinformsVersion>
   </PropertyGroup>
   <!-- Packages that come from https://github.com/dotnet/coreclr -->
   <PropertyGroup>