[docs] remove sshleifer from issue-template :(
+ Removes sshleifer from issue-templates :( 
+ For previous @sshleifer stuff, if it's in `src/` I put  @patrickvonplaten, if it's `examples/seq2seq` I put @patil-suraj.
+ @stas00 if you want to take over any thing or feel comfortable being the point person for certain things, feel free to suggest.


Thank you for the invitation, @sshleifer. 

My feeling is that a person in charge of any domain should have commit rights to that domain. Since I don't have those I'd be happy to be delegated to. (with the exception of fsmt since I wrote it)