Uninitialized value error wsrep_causal_reads (MySQL8.3 and Galera4)

[nblount]

Use of uninitialized value $myvar{"wsrep_causal_reads"} in concatenation (.) or
string at ./mysqltuner.pl line 6101 (#1)

The wsrep_causal_reads option has been deprecated. It has been replaced by [wsrep_sync_wait]
(https://galeracluster.com/library/documentation/mysql-wsrep-options.html#wsrep-sync-wait).

Maybe change line 6101 to:
if ( $myvar{'wsrep_causal_reads'} ) {
infoprint "Read consistency mode :" . $myvar{'wsrep_causal_reads'};
} else {
infoprint "Sync Wait mode : " . $myvar{'wsrep_sync_wait'};
}

I assume 0 for wsrep_sync_wait is the best value and it gets changes per session as required.