maint: add @slimnsour to developers registry

Author: oesteban

.maint/developers.json

@@ -22,6 +22,11 @@
     "name": "Lerma-Usabiaga, Garikoitz",
     "orcid": "0000-0001-9800-4816"
   },
+  {
+     "affiliation": "The Centre for Addiction and Mental Health",
+     "name": "Mansour, Salim",
+     "orcid": "0000-0002-1092-1650"
+  },
   {
     "affiliation": "Department of Psychology, University of Texas at Austin, TX, USA",
     "name": "Pisner, Derek",