Update RID graph

There are some releases that have already happened that we've missed:
* Fedora 30
* Linux Mint 19.1
* SLES 12.4

Others are upcoming / in beta:
* Debian 10 (June)
* Linux Mint 19.2 (announced, no date)
* openSUSE 15.1 (imminent)
* SLES 15.1 (June)
* Fedora 31 (October)
* Ubuntu 19.10 (October)
* Oracle Linux 8(.0) (Beta)

Commit migrated from dotnet/corefx@e486c46