[vs18.3] Stabilize package versions (#13233)

CI packages from vs18.3 are being produced with a `-release.{commitid}`
pre-release suffix because `DotNetFinalVersionKind` was never set when
the branch was stabilized.

This adds `<DotNetFinalVersionKind>release</DotNetFinalVersionKind>` to
`eng/Versions.props`, matching the pattern used in vs17.14 and other
servicing branches, so that packages are produced as stable `18.3.2`
versions.

Author: JanProvaznik

eng/Versions.props

@@ -3,8 +3,8 @@
   <Import Project="Version.Details.props" />
 
   <PropertyGroup>
-    <VersionPrefix>18.3.2</VersionPrefix>
-    <PreReleaseVersionLabel>release</PreReleaseVersionLabel> <!-- Keep next to VersionPrefix to create a conflict in forward-flow -->
+    <VersionPrefix>18.3.3</VersionPrefix><DotNetFinalVersionKind>release</DotNetFinalVersionKind> <!-- Keep next to VersionPrefix to create a conflict in forward-flow -->
+    <PreReleaseVersionLabel>servicing</PreReleaseVersionLabel>
     <PackageValidationBaselineVersion>18.0.2</PackageValidationBaselineVersion>
     <AssemblyVersion>15.1.0.0</AssemblyVersion>