setDumpHeader error after upgrading symfony/var-dumper to v5.3.4

After symfony/var-dumper was upgraded from v5.3.3 to v5.3.4 I'm getting:

Symfony\Component\VarDumper\Dumper\HtmlDumper::setDumpHeader(): Argument #1 ($header) must be of type string, null given, called in /Users/user/Documents/dev/project/vendor/maximebf/debugbar/src/DebugBar/DataFormatter/DebugBarVarDumper.php on line 288

Line 288 is $dumper->setDumpHeader(null);