Update $(MSBuildPackageReferenceVersion) to 17.14.28 (#265)

Author: jonathanpeppers

src/Microsoft.Android.Build.BaseTasks/MSBuildReferences.projitems

@@ -4,7 +4,7 @@
 <Project>
   <!--Import this file in projects needing to reference Microsoft.Build.*.dll -->
   <PropertyGroup>
-    <MSBuildPackageReferenceVersion Condition=" '$(MSBuildPackageReferenceVersion)' == '' ">17.14.8</MSBuildPackageReferenceVersion>
+    <MSBuildPackageReferenceVersion Condition=" '$(MSBuildPackageReferenceVersion)' == '' ">17.14.28</MSBuildPackageReferenceVersion>
     <LibZipSharpVersion Condition=" '$(LibZipSharpVersion)' == '' " >3.3.0</LibZipSharpVersion>
     <MonoUnixVersion>7.1.0-final.1.21458.1</MonoUnixVersion>
   </PropertyGroup>