Version: 3.5.1

Bug Description

For now for nullable properties this library generates typehint with ?, but this conflicts with PHP8 Union Types.
Generated typehint for union types now looks like ?OneType|OtherType, which is not valid PHP syntax.
Could you fix this for PHP8 please?

Possible Solution

Check PHP version and if it's larger than 8.0 - replace ? for |nullin typehint.