Update contributers section.

Author: tetron

contrib.md

@@ -3,9 +3,15 @@ Authors:
 * Peter Amstutz, Curii Inc. / Arvados; https://orcid.org/0000-0003-3566-7705
 * Michael R. Crusoe, CWL Project Lead; https://orcid.org/0000-0002-2961-9670
 * Kaushik Ghose, Seven Bridges Genomics, Inc; https://orcid.org/0000-0003-2933-1260
+
+Contributors to v1.2:
+
+* John Chilton <[email protected]>, Galaxy Project, Pennsylvania State University; https://orcid.org/0000-0002-6794-0756
+* Michael Franklin <[email protected]>, Peter MacCallum Cancer Centre and University of Melbourne
+* Bogdan Gavrilovic <[email protected]>, Seven Bridges Genomics
 * Stian Soiland-Reyes, University of Manchester; https://orcid.org/0000-0001-9842-9718
 
-Contributors: TBD 
+Incorporates the work of past authors and contributors to [CWL v1.0](https://www.commonwl.org/v1.0/Workflow.html) and [CWL v1.1](https://www.commonwl.org/v1.1/Workflow.html).
 
 This specification is a draft, and has not yet been approved as an official CWL standard.