Align with AspNetCore previews

Update the version metadata to align with ASP.NET Core, so we generate prerelease labels like "preview.8." or "rc.1.".

Author: martincostello

eng/Versions.props

@@ -6,8 +6,12 @@
     <PatchVersion>0</PatchVersion>
     <VersionPrefix>$(MajorVersion).$(MinorVersion).$(PatchVersion)</VersionPrefix>
     <PreReleaseVersionLabel>preview</PreReleaseVersionLabel>
+    <PreReleaseVersionIteration>8</PreReleaseVersionIteration>
+    <PreReleaseBrandingLabel>Preview $(PreReleaseVersionIteration)</PreReleaseBrandingLabel>
     <StabilizePackageVersion Condition="'$(StabilizePackageVersion)' == ''">false</StabilizePackageVersion>
     <DotNetFinalVersionKind Condition="'$(StabilizePackageVersion)' == 'true'">release</DotNetFinalVersionKind>
+    <IncludePreReleaseLabelInPackageVersion>true</IncludePreReleaseLabelInPackageVersion>
+    <IncludePreReleaseLabelInPackageVersion Condition=" '$(DotNetFinalVersionKind)' == 'release' ">false</IncludePreReleaseLabelInPackageVersion>
   </PropertyGroup>
 
 </Project>