Initial roadmap update post-2.1
Initial roadmap update post-2.1

Initial roadmap update now that .NET Core 2.1 has shipped.

Additional updates will come as planning continues and
draft specs are committed to master.
stephentoub/corefxlab,ericstj/corefxlab,stephentoub/corefxlab,adamsitnik/corefxlab,dotnet/corefxlab,stephentoub/corefxlab,stephentoub/corefxlab,ericstj/corefxlab,tarekgh/corefxlab,stephentoub/corefxlab,tarekgh/corefxlab,ahsonkhan/corefxlab,adamsitnik/corefxlab,dotnet/corefxlab,joshfree/corefxlab,KrzysztofCwalina/corefxlab,ericstj/corefxlab,ericstj/corefxlab,whoisj/corefxlab,ahsonkhan/corefxlab,whoisj/corefxlab,stephentoub/corefxlab,ericstj/corefxlab,KrzysztofCwalina/corefxlab,joshfree/corefxlab,ericstj/corefxlab