Bump MicroBuild to 2.0.171

Author: AArnott

Directory.Packages.props

@@ -5,7 +5,7 @@
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
 
-    <MicroBuildVersion>2.0.165</MicroBuildVersion>
+    <MicroBuildVersion>2.0.171</MicroBuildVersion>
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />