Java Implementation update

    Vert.x Json Schema, jsonschemafriend, networknt/json-schema-validator implement 2020-12

Author: boneyao

_data/validator-libraries-modern.yml

@@ -118,7 +118,7 @@
     - name: Vert.x Json Schema
       url: https://github.com/eclipse-vertx/vertx-json-schema
       notes: Validator for Eclipse Vert.x project JSON types.
-      date-draft: [2019-09]
+      date-draft: [2020-12, 2019-09]
       draft: [7]
       license: Apache License, Version 2.0
       notes: includes custom keywords support, custom dialect support, asynchronous validation
@@ -137,13 +137,13 @@
     - name: networknt/json-schema-validator
       url: https://github.com/networknt/json-schema-validator
       notes: Support OpenAPI 3.0 with Jackson parser 
-      date-draft: [2019-09]
+      date-draft: [2020-12, 2019-09]
       draft: [7, 6, 4]
       license: Apache License 2.0
     - name: jsonschemafriend
       url: https://github.com/jimblackler/jsonschemafriend
       notes:
-      date-draft: [2019-09]
+      date-draft: [2020-12, 2019-09]
       draft: [7, 6, 4, 3]
       license: Apache License 2.0
 - name: Kotlin