Update dependencies from...

Update dependencies from https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int build 20200806.4 (#3314)

[master] Update dependencies from dnceng/internal/dotnet-wpf-int
- Updates:
  - Microsoft.DotNet.Wpf.DncEng: from 5.0.0-preview.8.20406.3 to 5.0.0-preview.8.20406.4

eng/Version.Details.xml

@@ -61,9 +61,9 @@
       <Uri>https://github.com/dotnet/runtime</Uri>
       <Sha>2d9dbbb538322a7cc05397f5e2e15d445c7d3ff0</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="5.0.0-preview.8.20406.3">
+    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="5.0.0-preview.8.20406.4">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int</Uri>
-      <Sha>b966f5c54abdc64411c4fe96ab42d7f091ce12bd</Sha>
+      <Sha>58b6c51dc1ad5ab1dcf602b138bf06a9566cd2b7</Sha>
     </Dependency>
     <Dependency Name="System.IO.Packaging" Version="5.0.0-preview.8.20363.2" CoherentParentDependency="Microsoft.Private.Winforms">
       <Uri>https://github.com/dotnet/runtime</Uri>

eng/Versions.props

@@ -96,6 +96,6 @@
     <SystemReflectionMetadataLoadContextPackage>System.Reflection.MetadataLoadContext</SystemReflectionMetadataLoadContextPackage>
   </PropertyGroup>
   <PropertyGroup>
-    <MicrosoftDotNetWpfDncEngVersion>5.0.0-preview.8.20406.3</MicrosoftDotNetWpfDncEngVersion>
+    <MicrosoftDotNetWpfDncEngVersion>5.0.0-preview.8.20406.4</MicrosoftDotNetWpfDncEngVersion>
   </PropertyGroup>
 </Project>