fix: changing the start regex to support the old and new logs

[blackdynamo]

Mongodb has changed the structure of their logs in newer versions. The old structure was:

2020-03-10T13:18:09.076-0600 I NETWORK  [initandlisten] waiting for connections on port 27017

to

{"t":{"$date":"2020-03-10T19:15:53.408+0000"},"s":"I", "c":"NETWORK", "id":23016,"ctx":"listener","msg":"Waiting for connections","attr":{"port":27017,"ssl":"off"}}

This change is backwards compatible with older versions and windows as it's just a shorter version of the regular expression.