Update dependencies from...

Update dependencies from https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int build 20190729.20 (#1475)

- Microsoft.DotNet.Wpf.DncEng - 4.8.0-preview9.19379.20

eng/Version.Details.xml

@@ -75,9 +75,9 @@
       <Uri>https://github.com/dotnet/corefx</Uri>
       <Sha>80f411d58df8338ccd9430900b541a037a9cb383</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="4.8.0-preview8.19379.4">
+    <Dependency Name="Microsoft.DotNet.Wpf.DncEng" Version="4.8.0-preview9.19379.20">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-wpf-int</Uri>
-      <Sha>8248026ca9df8ba891de6de97b91779ecaa35983</Sha>
+      <Sha>5661e1f6587b4793365a4762dbda973a6547ad17</Sha>
     </Dependency>
     <Dependency Name="System.IO.Packaging" Version="4.6.0-preview8.19378.8" CoherentParentDependency="Microsoft.NETCore.App">
       <Uri>https://github.com/dotnet/corefx</Uri>

eng/Versions.props

@@ -112,6 +112,6 @@
       It is worth reiterating that this package *should not* be consumed to build the product.
   -->
   <PropertyGroup>
-    <MicrosoftDotNetWpfDncEngVersion>4.8.0-preview8.19379.4</MicrosoftDotNetWpfDncEngVersion>
+    <MicrosoftDotNetWpfDncEngVersion>4.8.0-preview9.19379.20</MicrosoftDotNetWpfDncEngVersion>
   </PropertyGroup>
 </Project>