Remove edtf data type from v1.0

cf. https://github.com/orgs/citation-style-language/teams/reviewers/discussions/6/comments/24

Author: bwiernik

schemas/input/csl-data.json

@@ -496,12 +496,6 @@
         }
       ]
     },
-    "edtf-datatype": {
-      "title": "EDTF datatype pattern",
-      "description": "CSL input supports EDTF, validated against this regular expression.",
-      "type": "string",
-      "pattern": "^[0-9-%~X?.\/]{4,}$"
-    },
     "date-variable": {
       "title": "Date content model.",
       "description": "The CSL input model supports two different date representations: an EDTF string (preferred), and a more structured alternative.",
@@ -535,9 +529,6 @@
             },
             "raw": {
               "type": "string"
-            },
-            "edtf": {
-              "$ref": "#/definitions/edtf-datatype"
             }
           },
           "additionalProperties": false