Add a compatibility note for MDExternalAccountBinding
[skip ci]
@@ -1300,6 +1300,7 @@ MDMessageCmd /etc/apache/md-message
<contextlist>
<context>server config</context>
</contextlist>
+ <compatibility>Available in version 2.4.52 and later</compatibility>
<usage>
<p>
Configure values for ACME "External Account Binding", a feature
