Add changelog for 2020-12 patch 1 update

Specifically draft-bhutton-json-schema-01 and draft-bhutton-json-schema-validation-01

Author: Relequestual

jsonschema-core.xml

@@ -3879,6 +3879,16 @@ https://example.com/schemas/common#/$defs/count/minimum
             </t>
             <t>
                 <list style="hanging">
+                    <t hangText="draft-bhutton-json-schema-01">
+                        <list style="symbols">
+                            <t>Improve and clarify the "type", "contains", "unevaluatedProperties", and "unevaluatedItems" keyword explanations</t>
+                            <t>Clarify various aspects of "canonical URIs"</t>
+                            <t>Comment on ambiguity around annotations and "additionalProperties"</t>
+                            <t>Clarify Vocabularies need not be formally defined</t>
+                            <t>Remove references to remaining media-type parameters</t>
+                            <t>Fix multiple examples</t>
+                        </list>
+                    </t>
                     <t hangText="draft-bhutton-json-schema-00">
                         <list style="symbols">
                             <t>"$schema" MAY change for embedded resources</t>

jsonschema-validation.xml

@@ -1441,6 +1441,12 @@
             </t>
             <t>
                 <list style="hanging">
+                    <t hangText="draft-bhutton-json-schema-validation-01">
+                        <list style="symbols">
+                            <t>Improve and clarify the "minContains" keyword explanation</t>
+                            <t>Remove the use of "production" in favour of "ABNF rule"</t>
+                        </list>
+                    </t>
                     <t hangText="draft-bhutton-json-schema-validation-00">
                         <list style="symbols">
                             <t>Correct email format RFC reference to 5321 instead of 5322</t>