Bump to non-preview version

Author: Tratcher

eng/Versions.props

@@ -2,8 +2,9 @@
   <PropertyGroup>
     <!-- This repo version -->
     <VersionPrefix>4.2.1</VersionPrefix>
-    <PreReleaseVersionLabel>preview</PreReleaseVersionLabel>
-    <PreReleaseVersionIteration>1</PreReleaseVersionIteration>
+    <PreReleaseVersionLabel>rtw</PreReleaseVersionLabel>
+    <PreReleaseVersionIteration></PreReleaseVersionIteration>
+    <DotNetFinalVersionKind Condition="'$(PreReleaseVersionLabel)' == 'rtw'">release</DotNetFinalVersionKind>
     <!-- Opt-out repo features -->
     <UsingToolXliff>false</UsingToolXliff>
     <!-- Libs -->