Update supported drafts for jsonschema-rs

Author: Stranger6667

_data/validator-libraries-modern.yml

@@ -201,7 +201,7 @@
       url: https://github.com/Stranger6667/jsonschema-rs
       notes: Fast due to compiling schema into a validation tree
       date-draft:
-      draft: [7, 6]
+      draft: [7, 6, 4]
       license: MIT
 - name: Objective-C
   implementations: