Update rxjs peer dependency to rxjs@"^7.0.0

[jfloodnet]

I'm currently using this with a resolution to version 7 and it's working smoothly.

[LayZeeDK]

Thank you for your interest in this package, @jfloodnet. It would be great to learn about your use cases! Feel free to reach out to me on LinkedIn or email

You are right in that the peer dependency could also support RxJS 7.x since the rxjs/operators namespace is still available, although deprecated. To support RxJS 8.x, the operator imports in the source code of multiScan should be pointed to the rxjs namespace.