New SHACL co-editor

Hi all,
I'm happy to announce that Dimitris has volunteered to help Holger with 
the editing of the spec. It is clear that the workload is too much for a 
single person and with Arthur having left the WG we need more resources 
put to this task.
I trust that everyone appreciates Dimitris's technical expertise and will 
join me in thanking him for helping out.
--
Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies - 
IBM Cloud