.Net Core 2.1 Preview2 is released.

We should move to the new version.

1. Roll-forward in RTM and Self-contained Application Servicing
   This can affect the creation of security patches.
2. Elimination of platform dependencies on libcurl
   We have some workarounds for libcurl. We should review this. "On Linux, you need to deploy libcurl yourself if you want to use the old HttpClient implementation."