Update dependencies from https://github.com/dotnet/corefx build 20200819.3 (#9073)

[release/3.1] Update dependencies from dotnet/corefx
- Updates:
  - Microsoft.Private.CoreFx.NETCoreApp: from 4.7.0-servicing.20419.1 to 4.7.0-servicing.20419.3
  - Microsoft.NETCore.Platforms: from 3.1.3 to 3.1.3

Author: dotnet-maestro[bot]

NuGet.config

@@ -7,7 +7,7 @@
   <packageSources>
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
-    <add key="darc-pub-dotnet-corefx-d1252eb" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-corefx-d1252ebf/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-corefx-d6302a7" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-corefx-d6302a72/nuget/v3/index.json" />
     <!--End: Package sources managed by Dependency Flow automation. Do not edit the sources above.-->
     <!--
       'src/test/PrepareTestAssets/PrepareTestAssets.proj' generates a NuGet.config file using this

eng/Version.Details.xml

@@ -20,15 +20,15 @@
     </Dependency>
     <Dependency Name="Microsoft.NETCore.Platforms" Version="3.1.3">
       <Uri>https://github.com/dotnet/corefx</Uri>
-      <Sha>d1252ebf87b135e66c95087b40302c2474b77206</Sha>
+      <Sha>d6302a72f8eafa326d7572a02acf8f3021ebb9e8</Sha>
     </Dependency>
     <Dependency Name="Microsoft.NETCore.Targets" Version="3.1.0">
       <Uri>https://github.com/dotnet/corefx</Uri>
       <Sha>0f7f38c4fd323b26da10cce95f857f77f0f09b48</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.7.0-servicing.20419.1">
+    <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.7.0-servicing.20419.3">
       <Uri>https://github.com/dotnet/corefx</Uri>
-      <Sha>d1252ebf87b135e66c95087b40302c2474b77206</Sha>
+      <Sha>d6302a72f8eafa326d7572a02acf8f3021ebb9e8</Sha>
     </Dependency>
     <Dependency Name="Microsoft.Win32.Registry.AccessControl" Version="4.7.0">
       <Uri>https://github.com/dotnet/corefx</Uri>

eng/Versions.props

@@ -59,7 +59,7 @@
     <!-- corefx -->
     <MicrosoftNETCorePlatformsPackageVersion>3.1.3</MicrosoftNETCorePlatformsPackageVersion>
     <MicrosoftNETCoreTargetsPackageVersion>3.1.0</MicrosoftNETCoreTargetsPackageVersion>
-    <MicrosoftPrivateCoreFxNETCoreAppPackageVersion>4.7.0-servicing.20419.1</MicrosoftPrivateCoreFxNETCoreAppPackageVersion>
+    <MicrosoftPrivateCoreFxNETCoreAppPackageVersion>4.7.0-servicing.20419.3</MicrosoftPrivateCoreFxNETCoreAppPackageVersion>
     <MicrosoftWin32RegistryAccessControlVersion>4.7.0</MicrosoftWin32RegistryAccessControlVersion>
     <MicrosoftWin32RegistryVersion>4.7.0</MicrosoftWin32RegistryVersion>
     <MicrosoftWin32SystemEventsVersion>4.7.0</MicrosoftWin32SystemEventsVersion>