Add @since tag to constant

Signed-off-by: Knut Ahlers <knut@ahlers.me>

lib/public/GroupInterface.php

@@ -51,6 +51,9 @@ interface GroupInterface {
 	//OBSOLETE const GET_DISPLAYNAME	= 0x00010000;
 	const COUNT_USERS		= 0x00100000;
 	const GROUP_DETAILS		= 0x01000000;
+	/**
+	 * @since 13.0.0
+	 */
 	const IS_ADMIN  = 0x10000000;
 
 	/**