Add versionadded info

Doc/lib/libimaplib.tex

@@ -184,6 +184,7 @@ data = authobject(response)
 
 \begin{methoddesc}{deleteacl}{mailbox, who}
   Delete the ACLs (remove any rights) set for who on mailbox.
+\versionadded{2.4}
 \end{methoddesc}
 
 \begin{methoddesc}{expunge}{}
@@ -248,6 +249,7 @@ data = authobject(response)
 
 \begin{methoddes}{myrights}{mailbox}
   Show my ACLs for a mailbox (i.e. the rights that I have on mailbox).
+\versionadded{2.4}
 \end{methoddesc}
 
 \begin{methoddesc}{namespace}{}