Finish removal of edtf datatype from v1.0.2

Author: bwiernik

schemas/input/csl-data.json

@@ -500,9 +500,6 @@
       "title": "Date content model.",
       "description": "The CSL input model supports two different date representations: an EDTF string (preferred), and a more structured alternative.",
       "anyOf": [
-        {
-          "$ref": "#/definitions/edtf-datatype"
-        },
         {
           "properties": {
             "date-parts": {