[FR]null value

[bezsahara]

Is your feature request related to a problem? Please describe. In order to delete a key in realtime db you can use either the delete method or send null as the value. Sending null as a value can be beneficial sometimes because you can use the update method to delete several keys at one request.

Describe the solution you'd like I would like a solution where None can be passed. Since requests lib does not want to change None values to null json.dumps can be used instead if None value is detected.

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.