Fix errors with php < 8 (#924)
Fix errors with php < 8 (#924)

Related issue https://github.com/zircote/swagger-php/issues/919

Co-authored-by: tlallement <071a7e25279a235c2aa911f11d08b0ee42be4f25@incert.lu>
zircote/swagger-php,DerManoMann/swagger-php