Thanks for the patch @prabha1997.
I have read it here that

core_version_req...

Thanks for the patch @prabha1997.

I have read it here that

core_version_requirement: ^8 || ^9
This specifies that the module is compatible with all versions of Drupal 8 and 9.

Further,
Most modules however will have to remove deprecated code to be compatible with Drupal 9. Therefore they will not able to be compatible with all versions of Drupal 8.

I think we shall apply this patch once D9 is available.