add default value to existing presta reconversionFrequency in migration

src/Migrations/Version20250107095819.php

@@ -21,6 +21,7 @@ final class Version20250107095819 extends AbstractMigration
     {
         // this up() migration is auto-generated, please modify it to your needs
         $this->addSql('ALTER TABLE prestataire CHANGE reconversionFrequency reconversionFrequency VARCHAR(50) DEFAULT \'once_a_month\'');
+        $this->addSql('UPDATE prestataire SET reconversionFrequency = \'once_a_month\' WHERE reconversionFrequency IS NULL');
     }
 
     public function down(Schema $schema) : void