Migration is missing PHP return types

[smxsm]

PHP Fatal error: Declaration of Endereco\Oxid6Client\Migrations\Version202
10614111035::preUp(Doctrine\DBAL\Schema\Schema $schema) must be compatible
with Doctrine\Migrations\AbstractMigration::preUp(Doctrine\DBAL\Schema\Sche
ma $schema): void in source/modules/endereco/endereco-oxid6-client/migration/data/Version
20210614111035.php on line 12

// is
public function preUp(Schema $schema)
// should be:
public function preUp(Schema $schema): void

same goes for up() and down() functions, ": void" must be added to get rid of the errors.

public function up(Schema $schema): void
public function down(Schema $schema): void