Merge in 'release/3.1' changes

Author: dotnet-bot

eng/Version.Details.xml

@@ -30,9 +30,9 @@
       <Uri>https://github.com/dotnet/corefx</Uri>
       <Sha>046765913dff824f9ed0f2d2fe0fb9b111906cf5</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NETCore.App" Version="3.1.9-servicing.20459.3">
+    <Dependency Name="Microsoft.NETCore.App" Version="3.1.17-servicing.21309.1">
       <Uri>https://github.com/dotnet/core-setup</Uri>
-      <Sha>1a04dd08e56bf52e88668c1ef2bd3f630ad442a5</Sha>
+      <Sha>b2b8c94156cbf9e2d2d5b26671a9b8e7d1225d9c</Sha>
     </Dependency>
     <Dependency Name="optimization.IBC.CoreCLR" Version="99.99.99-master-20190912.1">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-optimization</Uri>

eng/Versions.props

@@ -27,7 +27,7 @@
     <MicrosoftBclAsyncInterfacesVersion>1.0.0</MicrosoftBclAsyncInterfacesVersion>
     <SystemIOFileSystemAccessControlVersion>4.7.0</SystemIOFileSystemAccessControlVersion>
     <!-- core-setup -->
-    <MicrosoftNETCoreAppVersion>3.1.9-servicing.20459.3</MicrosoftNETCoreAppVersion>
+    <MicrosoftNETCoreAppVersion>3.1.17-servicing.21309.1</MicrosoftNETCoreAppVersion>
     <!-- dotnet-core-internal-tooling -->
     <IbcMergePackageVersion>5.0.6-beta.19203.1</IbcMergePackageVersion>
     <!-- dotnet-optimization -->