4.0.0

Feature
Relax HTTP 5XX error mask conditions
The payload returns a message and error that is dependant of the statusCode, not a unified unique generic one

BREAKING CHANGES:
Before

class ServiceUnavailable extends Therror.HTTP(503) {}
{
  error: 'InternalServerError',
  message: 'An internal server error occurred'
}

After

class ServiceUnavailable extends Therror.HTTP(503) {}
{
  error: 'ServiceUnavailable',
  message: 'Service Unavailable'
}