Update to latest buildtools version.

* This will fix the System.Net.WebException when trying to update the Versions repo in our Publishing definition.

BuildToolsVersion.txt

@@ -1 +1 @@
-2.1.0-preview1-02431-03
+2.1.0-preview1-02523-01

dependencies.props

@@ -14,7 +14,7 @@
     <StandardCurrentRef>6298244e25cf84d91e3cda9627315f2425274624</StandardCurrentRef>
     <ProjectNTfsCurrentRef>65f2e19b242b2d5ba1a3b058d01130cef8e8c045</ProjectNTfsCurrentRef>
     <ProjectNTfsTestILCCurrentRef>65f2e19b242b2d5ba1a3b058d01130cef8e8c045</ProjectNTfsTestILCCurrentRef>
-    <BuildToolsCurrentRef>0e808d0e044a03165109c14a7cad29a653e31fff</BuildToolsCurrentRef>
+    <BuildToolsCurrentRef>d6b3c82aed663b00f6075e6832008eac5e589948</BuildToolsCurrentRef>
     <CoreClrCurrentRef>0e808d0e044a03165109c14a7cad29a653e31fff</CoreClrCurrentRef>
   </PropertyGroup>
 
@@ -41,7 +41,7 @@
     <AppXRunnerVersion>1.0.3-prerelease-00921-01</AppXRunnerVersion>
     <CoreFxBaseLinePackageVersion>2.2.0-preview1-26216-02</CoreFxBaseLinePackageVersion>
     <XunitPerfAnalysisPackageVersion>1.0.0-beta-build0015</XunitPerfAnalysisPackageVersion>
-    <XunitNetcoreExtensionsVersion>2.1.0-preview1-02431-03</XunitNetcoreExtensionsVersion>
+    <XunitNetcoreExtensionsVersion>2.1.0-preview1-02523-01</XunitNetcoreExtensionsVersion>
 
     <CoreClrPackageVersion>2.1.0-preview1-26218-05</CoreClrPackageVersion>
     <DotNetHostPackageVersion>2.0.0-preview2-25310-02</DotNetHostPackageVersion>
@@ -53,7 +53,7 @@
   <!-- Package versions used as toolsets -->
   <PropertyGroup>
     <FeedTasksPackage>Microsoft.DotNet.Build.Tasks.Feed</FeedTasksPackage>
-    <FeedTasksPackageVersion>2.1.0-preview1-02431-03</FeedTasksPackageVersion>
+    <FeedTasksPackageVersion>2.1.0-preview1-02523-01</FeedTasksPackageVersion>
   </PropertyGroup>
 
   <!-- Package dependency verification/auto-upgrade configuration. -->
@@ -145,16 +145,21 @@
       <Path>$(MSBuildThisFileDirectory)BuildToolsVersion.txt</Path>
       <PackageId>Microsoft.DotNet.BuildTools</PackageId>
     </UpdateStep>
-    <XmlUpdateStep Include="CoreClr">
+    <XmlUpdateStep Include="BuildTools">
       <Path>$(MSBuildThisFileFullPath)</Path>
-      <ElementName>CoreClrPackageVersion</ElementName>
-      <PackageId>Microsoft.NETCore.Runtime.CoreCLR</PackageId>
+      <ElementName>XunitNetcoreExtensionsVersion</ElementName>
+      <PackageId>Microsoft.xunit.netcore.extensions</PackageId>
     </XmlUpdateStep>
     <XmlUpdateStep Include="BuildTools">
       <Path>$(MSBuildThisFileFullPath)</Path>
       <ElementName>FeedTasksPackageVersion</ElementName>
       <PackageId>$(FeedTasksPackage)</PackageId>
     </XmlUpdateStep>
+    <XmlUpdateStep Include="CoreClr">
+      <Path>$(MSBuildThisFileFullPath)</Path>
+      <ElementName>CoreClrPackageVersion</ElementName>
+      <PackageId>Microsoft.NETCore.Runtime.CoreCLR</PackageId>
+    </XmlUpdateStep>
   </ItemGroup>
 
   <PropertyGroup>