Example connection string invalid for inserting data

[OliBravo]

I tried to run the example from the Readme and I encountered an error trying to insert data.

This MongoDB deployment does not support retryable writes. Please add retryWrites=false to your connection string.

I had to adjust the connection string according to this error, so the valid one is like follows:

# Connect to demo server
con <- mongo("mtcars", url = "mongodb://readwrite:test@mongo.opencpu.org:43942/jeroen_test?retryWrites=false")