Change date of validation spec to 2022. Year has to be current or xml2rfc says no.

Relequestual · Relequestual · commit 98e3ee7756ea · 2022-04-28T13:30:21.000+01:00
diff --git a/jsonschema-validation.xml b/jsonschema-validation.xml
@@ -53,7 +53,7 @@
             </address>
         </author>
 
-        <date year="2021"/>
+        <date year="2022"/>
         <workgroup>Internet Engineering Task Force</workgroup>
         <keyword>JSON</keyword>
         <keyword>Schema</keyword>
