Fixes the sequence numbers of the Publisher since 11 was missing after 6...

...dcb7ff8e1689c371a85fb36bb415e62c693ea17


| 11     | The `Subscriber.onSubscribe` method on a given `Subscriber` instance MUST NOT be called more than once (based on object equality) |

was removed in commit https://github.com/reactive-streams/reactive-streams/commit/6dcb7ff8e1689c371a85fb36bb415e62c693ea17